tty: hvc_console: Call hvc_kick in hvc_write unconditionally

commit cfd956d upstream.

After hvc_write completes, call hvc_kick also in the case the output
buffer has been drained, to ensure tty_wakeup gets called.

This fixes that functions which wait for a drained buffer got stuck
occasionally.

Cc: stable <stable@kernel.org>
Closes: https://bugzilla.opensuse.org/show_bug.cgi?id=1230062
Signed-off-by: Fabian Vogt <fvogt@suse.de>
Link: https://lore.kernel.org/r/2011735.PYKUYFuaPT@fvogt-thinkpad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Vogtinator

drivers/tty/hvc/hvc_console.c

@@ -543,10 +543,10 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
 	}
 
 	/*
-	 * Racy, but harmless, kick thread if there is still pending data.
+	 * Kick thread to flush if there's still pending data
+	 * or to wakeup the write queue.
 	 */
-	if (hp->n_outbuf)
-		hvc_kick();
+	hvc_kick();
 
 	return written;
 }