Fix nrf52 initial stack pointer in ARMCC

Set the initial stack pointer to the end of ram so it matches
INITIAL_SP defined in RTX_CM_lib.h.

Author: c1728p9

hal/targets/cmsis/TARGET_NORDIC/TARGET_NRF5/TARGET_MCU_NRF52832/TOOLCHAIN_ARM_STD/startup_nrf52832.s

@@ -25,7 +25,7 @@
 ;   POSSIBILITY OF SUCH DAMAGE.
 ;   ---------------------------------------------------------------------------*/
 
-__initial_sp	EQU     0x20008000
+__initial_sp	EQU     0x20010000
 
                 PRESERVE8
                 THUMB