OMAP: serial: Remove incorrect disabling of IER interrupt

The recent patch to add RS485 contained a bug whereby the IER
interrupt was cleared down incorrectly.

This patch fixes the problem.
Signed-off-by: NMark Jackson <mpfj@newflow.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/omap-serial.c

@@ -1327,9 +1327,6 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 	pm_runtime_get_sync(up->dev);
 	spin_lock_irqsave(&up->port.lock, flags);
 
-	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
-	serial_out(up, UART_IER, up->ier);
-
 	/* Disable interrupts from this port */
 	mode = up->ier;
 	up->ier = 0;