fix(runtime): fix MISRA C:2012 Rule 10.1 in psci & realm_attest

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: Iac99dade27d53643d38a4d95c776a9f2c2000e09
diff --git a/runtime/rsi/psci.c b/runtime/rsi/psci.c
index 1762693..22b9283 100644
--- a/runtime/rsi/psci.c
+++ b/runtime/rsi/psci.c
@@ -313,7 +313,7 @@
 		break;
 	}
 
-	if ((res->action & FLAG_EXIT_TO_HOST) != 0) {
+	if (((unsigned int)res->action & FLAG_EXIT_TO_HOST) != 0U) {
 		rec_exit->exit_reason = RMI_EXIT_PSCI;
 	}
 }