portability: cmsis: use correct type for atomics

With the change of `atomic_t` from `int` to `long` there
were a few places where there was some type aliasing
occuring.

Update CMSIS to use `atomic_t` rather than `int` for all
atomic operations.

Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>

Author: cfriedt

subsys/portability/cmsis_rtos_v2/thread.c

@@ -26,8 +26,8 @@ static const osThreadAttr_t init_thread_attrs = {
 
 static sys_dlist_t thread_list;
 static struct cv2_thread cv2_thread_pool[CONFIG_CMSIS_V2_THREAD_MAX_COUNT];
-static uint32_t thread_num;
-static uint32_t thread_num_dynamic;
+static atomic_t thread_num;
+static atomic_t thread_num_dynamic;
 
 #if CONFIG_CMSIS_V2_THREAD_DYNAMIC_MAX_COUNT != 0
 static K_THREAD_STACK_ARRAY_DEFINE(cv2_thread_stack_pool,		     \