[PATCH] Serial: Add uart_insert_char()

Add uart_insert_char(), which handles inserting characters into the
flip buffer.  This helper function handles the correct semantics
for handling overrun in addition to inserting normal characters.

Signed-off-by: Russell King <rmk@arm.linux.org.uk>
diff --git a/drivers/serial/vr41xx_siu.c b/drivers/serial/vr41xx_siu.c
index 3078861..5d2ceb6 100644
--- a/drivers/serial/vr41xx_siu.c
+++ b/drivers/serial/vr41xx_siu.c
@@ -412,10 +412,8 @@
 
 		if (uart_handle_sysrq_char(port, ch, regs))
 			goto ignore_char;
-		if ((lsr & port->ignore_status_mask) == 0)
-			tty_insert_flip_char(tty, ch, flag);
-		if ((lsr & UART_LSR_OE) && (tty->flip.count < TTY_FLIPBUF_SIZE))
-			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+
+		uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
 
 	ignore_char:
 		lsr = siu_read(port, UART_LSR);