tty: rework break handling

Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/vme_scc.c b/drivers/char/vme_scc.c
index f17ac04..69c5afe 100644
--- a/drivers/char/vme_scc.c
+++ b/drivers/char/vme_scc.c
@@ -85,7 +85,7 @@
 static irqreturn_t scc_stat_int(int irq, void *data);
 static irqreturn_t scc_spcond_int(int irq, void *data);
 static void scc_setsignals(struct scc_port *port, int dtr, int rts);
-static void scc_break_ctl(struct tty_struct *tty, int break_state);
+static int scc_break_ctl(struct tty_struct *tty, int break_state);
 
 static struct tty_driver *scc_driver;
 
@@ -942,7 +942,7 @@
 }
 
 
-static void scc_break_ctl(struct tty_struct *tty, int break_state)
+static int scc_break_ctl(struct tty_struct *tty, int break_state)
 {
 	struct scc_port *port = (struct scc_port *)tty->driver_data;
 	unsigned long	flags;
@@ -952,6 +952,7 @@
 	SCCmod(TX_CTRL_REG, ~TCR_SEND_BREAK, 
 			break_state ? TCR_SEND_BREAK : 0);
 	local_irq_restore(flags);
+	return 0;
 }