staging: wilc1000: fix argument name of host_int_add_rx_gtk

This patch changes struct host_if_drv of host_int_add_rx_gtk function
declaration from hWFIDrv to hif_drv.
With this change, first argument of this function declaration and
definition has same name as hif_drv.

Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>