staging: brcm80211: rename key endian conversion functions

The key endian conversion functions in wl_cfg80211.c have been
renamed as the old names were misleasing.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>