staging: brcm80211: rename static functions in wl_cfg80211.c

The static functions in wl_cfg80211.c starting with wl_ prefix have
been renamed starting with brcmf_ prefix to be consistent.
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Reviewed-by: NRoland Vossen <rvossen@broadcom.com>
Reviewed-by: NFranky Lin <frankyl@broadcom.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>