imx: serial: be sure to stop xmit upon shutdown

needed to avoid continued transmission by hardware
while software already shuts down, which might
cause dangling characters to show up in hardware
queues when restarting the device.
Signed-off-by: NFabian Godehardt <fg@emlix.com>
Signed-off-by: NOskar Schirmer <os@emlix.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/serial/imx.c

@@ -634,6 +634,10 @@ static void imx_shutdown(struct uart_port *port)
 	struct imx_port *sport = (struct imx_port *)port;
 	unsigned long temp;
 
+	temp = readl(sport->port.membase + UCR2);
+	temp &= ~(UCR2_TXEN);
+	writel(temp, sport->port.membase + UCR2);
+
 	/*
 	 * Stop our timer.
 	 */