Target_UNO_91H: Remove custom _sbrk, update heap limits

Author: Deepika

targets/TARGET_RDA/TARGET_UNO_91H/device/TOOLCHAIN_ARM_STD/sys.cpp

@@ -166,6 +166,7 @@ SECTIONS
         __end__ = .;
         end = __end__;
         *(.heap*)
+        . = ORIGIN(DRAM) + LENGTH(DRAM);
         __HeapLimit = .;
     } > DRAM
     PROVIDE(__sbrk_start = ADDR(.heap));

targets/TARGET_RDA/TARGET_UNO_91H/device/TOOLCHAIN_GCC_ARM/TARGET_UNO_91H/RDA5981C.ld

@@ -29,24 +29,13 @@
 #define OS_CLOCK                160000000
 #endif
 
-#if defined(__CC_ARM)
+#if defined(__ARMCC_VERSION)
 extern uint32_t                 Image$$ARM_LIB_HEAP$$ZI$$Base[];
 extern uint32_t                 Image$$ARM_LIB_HEAP$$ZI$$Length[];
-extern uint32_t                 Image$$ARM_LIB_STACK$$ZI$$Base[];
-extern uint32_t                 Image$$ARM_LIB_STACK$$ZI$$Length[];
-#define HEAP_START              ((unsigned char*) Image$$ARM_LIB_HEAP$$ZI$$Base)
-#define HEAP_SIZE               ((uint32_t) Image$$ARM_LIB_HEAP$$ZI$$Length)
-#define ISR_STACK_START         ((unsigned char*)Image$$ARM_LIB_STACK$$ZI$$Base)
-#define ISR_STACK_SIZE          ((uint32_t)Image$$ARM_LIB_STACK$$ZI$$Length)
+#define HEAP_START              Image$$ARM_LIB_HEAP$$ZI$$Base
+#define HEAP_SIZE               Image$$ARM_LIB_HEAP$$ZI$$Length
 #elif defined(__GNUC__)
-extern uint32_t                 __StackTop[];
-extern uint32_t                 __StackLimit[];
-extern uint32_t                 __end__[];
-extern uint32_t                 __HeapLimit[];
-#define HEAP_START              ((unsigned char*)__end__)
-#define HEAP_SIZE               ((uint32_t)((uint32_t)__HeapLimit - (uint32_t)HEAP_START))
-#define ISR_STACK_START         ((unsigned char*)__StackLimit)
-#define ISR_STACK_SIZE          ((uint32_t)((uint32_t)__StackTop - (uint32_t)__StackLimit))
+/* No region declarations needed */
 #elif defined(__ICCARM__)
 /* No region declarations needed */
 #else