services: fix switch statements to comply with MISRA rules

Ensure (where possible) that switch statements in services comply with
MISRA rules 16.1 - 16.7.

Change-Id: I47bf6ed4a026201e6fe125ce51842482e99e8bb0
Signed-off-by: Jonathan Wright <jonathan.wright@arm.com>
diff --git a/services/spd/opteed/opteed_main.c b/services/spd/opteed/opteed_main.c
index 13a307a..3d67980 100644
--- a/services/spd/opteed/opteed_main.c
+++ b/services/spd/opteed/opteed_main.c
@@ -311,6 +311,7 @@
 		 * OPTEE. Jump back to the original C runtime context.
 		 */
 		opteed_synchronous_sp_exit(optee_ctx, x1);
+		break;
 
 
 	/*
@@ -345,6 +346,7 @@
 		 * return value to the caller
 		 */
 		opteed_synchronous_sp_exit(optee_ctx, x1);
+		break;
 
 	/*
 	 * OPTEE is returning from a call or being preempted from a call, in