fix compile error

Including unused header file, "cmsis-os.h",  causes compile errors.
This commit fixes it.

Signed-off-by: Heuisam Kwag <[email protected]>

Author: heuisam

targets/TARGET_Samsung/TARGET_SIDK_S1SBP6A/watchdog_api.c

@@ -25,7 +25,6 @@
 
 #include <string.h>
 #include <stdio.h>
-#include "cmsis_os.h"
 #include "cmsis.h"
 #include "watchdog_api.h"