serial: sh-sci: Use dev_dbg() to log an error message

Since the driver cannot return from overrun error if characters
are output during overrun process, use dev_dbg() instead of
dev_notice() to log the error message of overrun in syslog.

Based on a patch by Hisashi Nakamura.
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sh-sci.c

@@ -858,7 +858,7 @@ static int sci_handle_fifo_overrun(struct uart_port *port)
 		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 		tty_flip_buffer_push(tport);
 
-		dev_notice(port->dev, "overrun error\n");
+		dev_dbg(port->dev, "overrun error\n");
 		copied++;
 	}