fix(runtime): fix MISRA C:2012 Rule 10.1 in handler.c

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: Id8862804cf1c31133a87d04667ed468d5717b349
diff --git a/runtime/core/handler.c b/runtime/core/handler.c
index 9b2f7df..dcbf970 100644
--- a/runtime/core/handler.c
+++ b/runtime/core/handler.c
@@ -194,7 +194,7 @@
 		INFO("SMC_RMM_%-21s", handler->fn_name);
 
 		/* Print arguments */
-		num = handler->type & 0xFF;
+		num = (unsigned int)handler->type & 0xFFU;
 		assert(num <= MAX_NUM_ARGS);
 
 		for (unsigned int i = 0U; i < num; i++) {
@@ -220,7 +220,7 @@
 		   ((function_id == SMC_RMM_RTT_DESTROY) ||
 		    (function_id == SMC_RMM_DATA_DESTROY)))) {
 			/* Print output values */
-			num = (handler->type >> 8) & 0xFF;
+			num = ((unsigned int)handler->type >> 8) & 0xFFU;
 			assert(num <= MAX_NUM_OUTPUT_VALS);
 
 			for (unsigned int i = 1U; i <= num; i++) {