USB: serial: upd78f0730: make constants static

Some local constants don't change from call to call and are good
candidates to become static. This will prevent copying of these
constants to stack during runtime.

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

drivers/usb/serial/upd78f0730.c

···
 static speed_t upd78f0730_get_baud_rate(struct tty_struct *tty)
 {
 	const speed_t baud_rate = tty_get_baud_rate(tty);
-	const speed_t supported[] = {
+	static const speed_t supported[] = {
 		0, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 153600
 	};
 	int i;
···
 
 static int upd78f0730_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
-	struct upd78f0730_open_close request = {
+	static const struct upd78f0730_open_close request = {
 		.opcode = UPD78F0730_CMD_OPEN_CLOSE,
 		.state = UPD78F0730_PORT_OPEN
 	};
···
 
 static void upd78f0730_close(struct usb_serial_port *port)
 {
-	struct upd78f0730_open_close request = {
+	static const struct upd78f0730_open_close request = {
 		.opcode = UPD78F0730_CMD_OPEN_CLOSE,
 		.state = UPD78F0730_PORT_CLOSE
 	};