staging: brcm80211: cleanup of softmac macro EDCF_ENAB()

Since structure member pub->_wme is set to AUTO early in init, macro
EDCF_ENAB is always 'true' after that. All code that uses ECDF_ENAB()
appears in the code flow after the init.

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