Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/mips/bcm63xx/dev-flash.c b/arch/mips/bcm63xx/dev-flash.c
index 172dd83..a109393 100644
--- a/arch/mips/bcm63xx/dev-flash.c
+++ b/arch/mips/bcm63xx/dev-flash.c
@@ -94,6 +94,7 @@
 		case STRAPBUS_6368_BOOT_SEL_PARALLEL:
 			return BCM63XX_FLASH_TYPE_PARALLEL;
 		}
+		/* fall through */
 	default:
 		return -EINVAL;
 	}