USB: serial: mos7840: remove set but not used variables 'number, serial'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/usb/serial/mos7840.c: In function 'mos7840_send_cmd_write_baud_rate':
drivers/usb/serial/mos7840.c:1584:16: warning:
variable 'number' set but not used [-Wunused-but-set-variable]

drivers/usb/serial/mos7840.c: In function 'mos7840_change_port_settings':
drivers/usb/serial/mos7840.c:1695:21: warning:
variable 'serial' set but not used [-Wunused-but-set-variable]

'number' never used since introduction in commit 3f5429746d91 ("USB: Moschip
7840 USB-Serial Driver")

'serial' not used since commit 5833041f1b13 ("USB: serial: remove unnecessary
reinitialisations of urb->dev")

Signed-off-by: YueHaibing <[e-mail]>
Signed-off-by: Johan Hovold <[e-mail]>

drivers/usb/serial/mos7840.c

···
 	int divisor = 0;
 	int status;
 	__u16 Data;
-	unsigned char number;
 	__u16 clk_sel_val;
 	struct usb_serial_port *port;
 
···
 
 	if (mos7840_serial_paranoia_check(port->serial, __func__))
 		return -1;
-
-	number = mos7840_port->port->port_number;
 
 	dev_dbg(&port->dev, "%s - baud = %d\n", __func__, baudRate);
 	/* reset clk_uart_sel in spregOffset */
···
 	int status;
 	__u16 Data;
 	struct usb_serial_port *port;
-	struct usb_serial *serial;
 
 	if (mos7840_port == NULL)
 		return;
···
 
 	if (mos7840_serial_paranoia_check(port->serial, __func__))
 		return;
-
-	serial = port->serial;
 
 	if (!mos7840_port->open) {
 		dev_dbg(&port->dev, "%s - port not opened\n", __func__);