serial: timbuart: Staticize local symbols

These local symbols are used only in this file.
Fix the following sparse warnings:

drivers/tty/serial/timbuart.c:165:6: warning: symbol 'timbuart_handle_rx_port' was not declared. Should it be static?
drivers/tty/serial/timbuart.c:187:6: warning: symbol 'timbuart_tasklet' was not declared. Should it be static?
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/timbuart.c

@@ -162,7 +162,7 @@ static void timbuart_handle_tx_port(struct uart_port *port, u32 isr, u32 *ier)
 	dev_dbg(port->dev, "%s - leaving\n", __func__);
 }
 
-void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *ier)
+static void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *ier)
 {
 	if (isr & RXFLAGS) {
 		/* Some RX status is set */
@@ -184,7 +184,7 @@ void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *ier)
 	dev_dbg(port->dev, "%s - leaving\n", __func__);
 }
 
-void timbuart_tasklet(unsigned long arg)
+static void timbuart_tasklet(unsigned long arg)
 {
 	struct timbuart_port *uart = (struct timbuart_port *)arg;
 	u32 isr, ier = 0;