fix(rmm): fix MISRA C:2012 Rule 10.4

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: I03630ef02c8c294a552ad10523d9c78091ce161a
diff --git a/runtime/core/handler.c b/runtime/core/handler.c
index 560aa9f..50e655e 100644
--- a/runtime/core/handler.c
+++ b/runtime/core/handler.c
@@ -16,10 +16,10 @@
 #include <utils_def.h>
 
 /* Maximum number of supported arguments */
-#define MAX_NUM_ARGS		5
+#define MAX_NUM_ARGS		5U
 
 /* Maximum number of output values */
-#define MAX_NUM_OUTPUT_VALS	4
+#define MAX_NUM_OUTPUT_VALS	4U
 
 #define RMI_STATUS_STRING(_id)[RMI_##_id] = #_id