n_tty: remove superfluous return from n_tty_receive_signal_char

A return at the end of a void-returning function is superfluous. Get rid
of it.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210505091928.22010-11-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/n_tty.c

@@ -1245,7 +1245,6 @@ n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
 		commit_echoes(tty);
 	} else
 		process_echoes(tty);
-	return;
 }
 
 /**