Fixes the bug of having &mbed_fault_context argument instead of mbed_fault_context in mbed_fault_handler.

Author: andrewc-arm

platform/source/TARGET_CORTEX_M/TOOLCHAIN_ARM/except.S

@@ -150,7 +150,8 @@ Fault_Handler_Continue2
                 MRS      R2,CONTROL               ; Get CONTROL Reg
                 STR      R2,[R1]
                 MOV      R0,R12
-                LDR      R1,=mbed_fault_context
+                LDR      R3,=mbed_fault_context
+                LDR      R1,[R3]
                 BL       mbed_fault_handler
 #endif                    
                 B        .                        ; Just in case we come back here                

platform/source/TARGET_CORTEX_M/TOOLCHAIN_GCC/except.S

@@ -183,7 +183,8 @@ Fault_Handler_Continue2:
         MRS      R2,CONTROL               // Get CONTROL Reg
         STR      R2,[R1]
         MOV      R0,R12
-        LDR      R1,=mbed_fault_context
+        LDR      R3,=mbed_fault_context
+        LDR      R1,[R3]
         BL       mbed_fault_handler
 #endif
         B        .                        // Just in case we come back here   

platform/source/TARGET_CORTEX_M/TOOLCHAIN_IAR/except.S

@@ -145,7 +145,8 @@ Fault_Handler_Continue2
                 MRS     R2,CONTROL               ; Get CONTROL Reg
                 STR     R2,[R1]
                 MOV     R0,R12
-                LDR     R1,=mbed_fault_context
+                LDR     R3,=mbed_fault_context
+                LDR     R1,[R3]
                 BL      mbed_fault_handler 
 #endif                
                 B       .                        ; Just in case we come back here