brcm80211: smac: replace own access category definitions with mac80211 enum

The brcmsmac had own definitions for the access categories. The mac80211
header provides these as well as they are used in the conf_tx callback.
As the definitions did not match the driver configured the tx parameters
to the wrong queue.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>