misc: sgi-gru: fix fall-through annotations

Replace "fallthru" with a proper "fall through" annotation.

This fix is part of the ongoing efforts to enabling
-Wimplicit-fallthrough

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/sgi-gru/grukservices.c

@@ -634,7 +634,7 @@ static int send_noop_message(void *cb, struct gru_message_queue_desc *mqd,
 			break;
 		case CBSS_PAGE_OVERFLOW:
 			STAT(mesq_noop_page_overflow);
-			/* fallthru */
+			/* fall through */
 		default:
 			BUG();
 		}
@@ -792,7 +792,7 @@ static int send_message_failure(void *cb, struct gru_message_queue_desc *mqd,
 		break;
 	case CBSS_PAGE_OVERFLOW:
 		STAT(mesq_page_overflow);
-		/* fallthru */
+		/* fall through */
 	default:
 		BUG();
 	}