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