mt7601u: constify usb_device_id

usb_device_id are not supposed to change at runtime. All functions
working with usb_device_id provided by <linux/usb.h> work with
const usb_device_id. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mediatek/mt7601u/usb.c

@@ -19,7 +19,7 @@
 #include "usb.h"
 #include "trace.h"
 
-static struct usb_device_id mt7601u_device_table[] = {
+static const struct usb_device_id mt7601u_device_table[] = {
 	{ USB_DEVICE(0x0b05, 0x17d3) },
 	{ USB_DEVICE(0x0e8d, 0x760a) },
 	{ USB_DEVICE(0x0e8d, 0x760b) },