serial: imx: remove the redundant code

In the imx_startup(), we will reset the uart port which will reset all
the FIFOs, including the URXD.

So the code to clear the RX FIFO is redundant. Just remove it.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/imx.c

@@ -1161,15 +1161,6 @@ static int imx_startup(struct uart_port *port)
 		temp |= UCR2_IRTS;
 	writel(temp, sport->port.membase + UCR2);
 
-	if (USE_IRDA(sport)) {
-		/* clear RX-FIFO */
-		int i = 64;
-		while ((--i > 0) &&
-			(readl(sport->port.membase + URXD0) & URXD_CHARRDY)) {
-			barrier();
-		}
-	}
-
 	if (!is_imx1_uart(sport)) {
 		temp = readl(sport->port.membase + UCR3);
 		temp |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP;