staging: wlan-ng: malformed SPDX-License-Identifier

Correct malformed SPDX-License-Identifier so that it
matches Linux kernel comment coding style.

Signed-off-by: Branden Bonaby <brandonbonaby94@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wlan-ng/hfa384x_usb.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: (GPL-2.0 OR MPL-1.1)
+/* SPDX-License-Identifier: (GPL-2.0 OR MPL-1.1) */
 /* src/prism2/driver/hfa384x_usb.c
  *
  * Functions that talk to the USB variantof the Intersil hfa384x MAC