zd1211rw: 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/zydas/zd1211rw/zd_usb.c

@@ -35,7 +35,7 @@
 #include "zd_mac.h"
 #include "zd_usb.h"
 
-static struct usb_device_id usb_ids[] = {
+static const struct usb_device_id usb_ids[] = {
 	/* ZD1211 */
 	{ USB_DEVICE(0x0105, 0x145f), .driver_info = DEVICE_ZD1211 },
 	{ USB_DEVICE(0x0586, 0x3401), .driver_info = DEVICE_ZD1211 },