staging: brcm80211: cleanup struct wlc_info definition

The structure definition for wlc_info contained a lot of fields that
are only initialized or not used at all. These have been removed to
cleanup the driver code.

Signed-off-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>