tty/serial: serial8250_set_divisor() can be static

drivers/tty/serial/8250/8250_core.c:2503:6: sparse: symbol 'serial8250_set_divisor' was not declared. Should it be static?
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_core.c

@@ -2500,7 +2500,7 @@ static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
 	return cval;
 }
 
-void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
+static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
 			    unsigned int quot, unsigned int quot_frac)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);