Ensure the flow through switch statements is clear

Ensure case clauses:
*   Terminate with an unconditional break, return or goto statement.
*   Use conditional break, return or goto statements as long as the end
    of the case clause is unreachable; such case clauses must terminate
    with assert(0) /* Unreachable */ or an unconditional  __dead2 function
    call
*   Only fallthough when doing otherwise would result in less
    readable/maintainable code; such case clauses must terminate with a
    /* Fallthrough */ comment to make it clear this is the case and
    indicate that a fallthrough is intended.

This reduces the chance of bugs appearing due to unintended flow through a
switch statement

Change-Id: I70fc2d1f4fd679042397dec12fd1982976646168
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/bl1/bl1_fwu.c b/bl1/bl1_fwu.c
index 25be577..28b9eb9 100644
--- a/bl1/bl1_fwu.c
+++ b/bl1/bl1_fwu.c
@@ -86,11 +86,9 @@
 
 	case FWU_SMC_UPDATE_DONE:
 		bl1_fwu_done((void *)x1, NULL);
-		/* We should never return from bl1_fwu_done() */
-		break;
 
 	default:
-		assert(0);
+		assert(0); /* Unreachable */
 		break;
 	}
 
@@ -747,7 +745,7 @@
 
 	case IMAGE_STATE_EXECUTED:
 	default:
-		assert(0);
+		assert(0); /* Unreachable */
 		break;
 	}