staging: gdm72xx: fix unused variable warning in gdm_usb_send

This patch fixes an unused variable warning in gdm_usb_send
(when CONFIG_WIMAX_GDM72XX_K_MODE=n), which was introduced in
commit 1a276b8 (staging:
gdm72xx: protect access of rx / tx structs).

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Ben Chan <benchan@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gdm72xx/gdm_usb.c

@@ -316,7 +316,10 @@ static int gdm_usb_send(void *priv_dev, void *data, int len,
 	int no_spc = 0, ret;
 	u8 *pkt = data;
 	u16 cmd_evt;
-	unsigned long flags, flags2;
+	unsigned long flags;
+#ifdef CONFIG_WIMAX_GDM72XX_K_MODE
+	unsigned long flags2;
+#endif /* CONFIG_WIMAX_GDM72XX_K_MODE */
 
 	if (!udev->usbdev) {
 		dev_err(&usbdev->dev, "%s: No such device\n", __func__);