staging: brcm80211: remove wireless extensions support from brcmfmac

The brcmfmac driver contained functions for wireless extensions
support. However, brcmfmac is intended to be a cfg80211 driver
so all the entire source file is obsolete.

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>