Fix example links in MBRBlockDevice.md

Update examples because source repo structure changed.

Author: Amanda Butler

docs/api/storage/MBRBlockDevice.md

@@ -19,11 +19,11 @@ You can view more information about the configurable settings and functions in t
 
 Partition a heap backed block device into two partitions. This example also uses the [HeapBlockDevice](heapblockdevice.html).
 
-[![View code](https://www.mbed.com/embed/?url=https://github.com/ARMmbed/mbed-os-examples-docs_only/tree/master/MBRBlockDevice_ex_1/)](https://github.com/ARMmbed/mbed-os-examples-docs_only/tree/master/MBRBlockDevice_ex_1/main.cpp)
+[![View code](https://www.mbed.com/embed/?url=https://github.com/ARMmbed/mbed-os-examples-docs_only/blob/master/blockdevices/MBRBlockDevice/MBRBlockDevice_ex_1/)](https://github.com/ARMmbed/mbed-os-examples-docs_only/blob/master/blockdevices/MBRBlockDevice/MBRBlockDevice_ex_1/main.cpp)
 
 Partition an SD card, and format the new partition with a FAT filesystem. A PC will now be able to recognize the SD card.
 
-[![View code](https://www.mbed.com/embed/?url=https://github.com/ARMmbed/mbed-os-examples-docs_only/tree/master/MBRBlockDevice_ex_2/)](https://github.com/ARMmbed/mbed-os-examples-docs_only/tree/master/MBRBlockDevice_ex_2/main.cpp)
+[![View code](https://www.mbed.com/embed/?url=https://github.com/ARMmbed/mbed-os-examples-docs_only/blob/master/blockdevices/MBRBlockDevice/MBRBlockDevice_ex_2/)](https://github.com/ARMmbed/mbed-os-examples-docs_only/blob/master/blockdevices/MBRBlockDevice/MBRBlockDevice_ex_2/main.cpp)
 
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