staging: wlan-ng/hfa384x_usb.c: add blank line after declarations

This patch fixes the following checkpatch.pl issues in hfa384x_usb.c:
WARNING: Missing a blank line after declarations
Signed-off-by: Quentin Lee <lee.rhapsody@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wlan-ng/hfa384x_usb.c

@@ -3705,6 +3705,7 @@ static void hfa384x_usbout_callback(struct urb *urb)
 		case -EPIPE:
 			{
 				hfa384x_t *hw = wlandev->priv;
+
 				netdev_warn(hw->wlandev->netdev,
 					    "%s tx pipe stalled: requesting reset\n",
 					    wlandev->netdev->name);