Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index 1e4d5b9..fcb91bf 100644
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -1259,8 +1259,7 @@
 	if (sanity_check(info, tty->name, "ioctl"))
 		return -ENODEV;
 
-	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
-	    (cmd != TIOCMIWAIT)) {
+	if (cmd != TIOCMIWAIT) {
 		if (tty_io_error(tty))
 		    return -EIO;
 	}