staging:wlan-ng:Fix sparse warning cast to restricted __le16

This patch fixes the following sparse warnings:
drivers/staging/wlan-ng/hfa384x_usb.c:3582:14: warning: cast to
restricted __le16
drivers/staging/wlan-ng/hfa384x_usb.c:3584:19: warning: cast to
restricted __le16
by changing the annotations in the struct declaration.

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>