cpu/cortex-mX_common: bugfix to arch_stack_init

- fixed cortex-[m0|m3|m4]

cpu/cortex-m0_common/thread_arch.c

@@ -28,7 +28,6 @@
 #include "cpu.h"
 #include "kernel_internal.h"
 
-
 /**
  * @name noticeable marker marking the beginning of a stack segment
  *
@@ -67,7 +66,7 @@ char *thread_arch_stack_init(void *(*task_func)(void *),
                              int stack_size)
 {
     uint32_t *stk;
-    stk = (uint32_t *)((uint32_t *)stack_start + stack_size);
+    stk = (uint32_t *)((uint32_t)stack_start + stack_size);
 
     /* marker */
     stk--;

cpu/cortex-m3_common/thread_arch.c

@@ -57,7 +57,7 @@ static void context_restore(void) NORETURN;
 char *thread_arch_stack_init(void *(*task_func)(void *), void *arg, void *stack_start, int stack_size)
 {
     uint32_t *stk;
-    stk = (uint32_t *)((uint32_t *)stack_start + stack_size);
+    stk = (uint32_t *)((uint32_t)stack_start + stack_size);
 
     /* marker */
     stk--;

cpu/cortex-m4_common/thread_arch.c

@@ -63,7 +63,7 @@ char *thread_arch_stack_init(void *(*task_func)(void *),
                              int stack_size)
 {
     uint32_t *stk;
-    stk = (uint32_t *)((uint32_t*)stack_start + stack_size);
+    stk = (uint32_t *)((uint32_t)stack_start + stack_size);
 
     /* marker */
     stk--;