n_tty: Simplify input_available_p()

Greg,

Please note this patch requires
   n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0

Regards,
Peter Hurley
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/n_tty.c

@@ -1900,13 +1900,10 @@ static inline int input_available_p(struct tty_struct *tty, int poll)
 	struct n_tty_data *ldata = tty->disc_data;
 	int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;
 
-	if (ldata->icanon && !L_EXTPROC(tty)) {
-		if (ldata->canon_head != ldata->read_tail)
-			return 1;
-	} else if (read_cnt(ldata) >= amt)
-		return 1;
-
-	return 0;
+	if (ldata->icanon && !L_EXTPROC(tty))
+		return ldata->canon_head != ldata->read_tail;
+	else
+		return read_cnt(ldata) >= amt;
 }
 
 /**