serial: sh-sci: Fix fifo stall on SH7760/SH7780/SH7785 SCIF.

There was an off-by-1 in the SCRFDR calculation that caused writes over
128-bytes to hang in the FIFO. Fix it up.

Signed-off-by: Yutaro Ebihara <ebiharaml@si-linux.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/drivers/serial/sh-sci.c b/drivers/serial/sh-sci.c
index a8c116b..9d244d1 100644
--- a/drivers/serial/sh-sci.c
+++ b/drivers/serial/sh-sci.c
@@ -414,12 +414,12 @@
     defined(CONFIG_CPU_SUBTYPE_SH7785)
 static inline int scif_txroom(struct uart_port *port)
 {
-	return SCIF_TXROOM_MAX - (sci_in(port, SCTFDR) & 0x7f);
+	return SCIF_TXROOM_MAX - (sci_in(port, SCTFDR) & 0xff);
 }
 
 static inline int scif_rxroom(struct uart_port *port)
 {
-	return sci_in(port, SCRFDR) & 0x7f;
+	return sci_in(port, SCRFDR) & 0xff;
 }
 #else
 static inline int scif_txroom(struct uart_port *port)