Add using namespace::class for classes newly added to mbed namespace

`using namespac:class` is need to maintian backwards compatibility,
It is used under MBED_NO_NAMESPACE macro, to avoid polluting users
namespace.

Author: deepikabhavnani

features/filesystem/bd/BlockDevice.h

@@ -226,4 +226,11 @@ class BlockDevice
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::BlockDevice;
+using mbed::bd_addr_t;
+using mbed::bd_size_t;
+#endif
+
 #endif

features/filesystem/bd/BufferedBlockDevice.h

@@ -169,4 +169,9 @@ class BufferedBlockDevice : public BlockDevice {
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::BufferedBlockDevice;
+#endif
+
 #endif

features/filesystem/bd/ChainingBlockDevice.h

@@ -183,4 +183,9 @@ class ChainingBlockDevice : public BlockDevice
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::ChainingBlockDevice;
+#endif
+
 #endif

features/filesystem/bd/ExhaustibleBlockDevice.h

@@ -163,4 +163,9 @@ class ExhaustibleBlockDevice : public BlockDevice
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::ExhaustibleBlockDevice;
+#endif
+
 #endif

features/filesystem/bd/FlashSimBlockDevice.h

@@ -145,4 +145,9 @@ class FlashSimBlockDevice : public BlockDevice {
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::FlashSimBlockDevice;
+#endif
+
 #endif

features/filesystem/bd/HeapBlockDevice.h

@@ -28,8 +28,6 @@ namespace mbed {
 /** \addtogroup filesystem */
 /** @{*/
 
-
-
 /** Lazily allocated heap-backed block device
  *
  * Useful for simulating a block device and tests
@@ -160,4 +158,9 @@ class HeapBlockDevice : public BlockDevice
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::HeapBlockDevice;
+#endif
+
 #endif

features/filesystem/bd/MBRBlockDevice.h

@@ -260,4 +260,9 @@ class MBRBlockDevice : public BlockDevice
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::MBRBlockDevice;
+#endif
+
 #endif

features/filesystem/bd/ObservingBlockDevice.h

@@ -147,4 +147,9 @@ class ObservingBlockDevice : public BlockDevice
 /** @}*/
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::ObservingBlockDevice;
+#endif
+
 #endif

features/filesystem/bd/ProfilingBlockDevice.h

@@ -184,6 +184,11 @@ class ProfilingBlockDevice : public BlockDevice
     bd_size_t _erase_count;
 };
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::ProfilingBlockDevice;
+#endif
+
 /** @}*/
 } // namespace mbed
 

features/filesystem/bd/ReadOnlyBlockDevice.h

@@ -136,6 +136,11 @@ class ReadOnlyBlockDevice : public BlockDevice
     BlockDevice *_bd;
 };
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::ReadOnlyBlockDevice;
+#endif
+
 /** @}*/
 } // namespace mbed
 

features/filesystem/bd/SlicingBlockDevice.h

@@ -28,7 +28,6 @@ namespace mbed {
 /** \addtogroup filesystem */
 /** @{*/
 
-
 /** Block device for mapping to a slice of another block device
  *
  *  @code
@@ -170,6 +169,11 @@ class SlicingBlockDevice : public BlockDevice
     bd_size_t _stop;
 };
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::SlicingBlockDevice;
+#endif
+
 /** @}*/
 } // namespace mbed
 

features/filesystem/fat/FATFileSystem.h

@@ -273,4 +273,9 @@ class FATFileSystem : public FileSystem {
 
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::FATFileSystem;
+#endif
+
 #endif

features/filesystem/littlefs/LittleFileSystem.h

@@ -282,4 +282,9 @@ class LittleFileSystem : public mbed::FileSystem {
 
 } // namespace mbed
 
+// Added "using" for backwards compatibility
+#ifndef MBED_NO_NAMESPACE
+using mbed::LittleFileSystem;
+#endif
+
 #endif