staging: brcm80211: remove unused definitions from dhd.h

The header file dhd.h contained a number of macro definitions that
are not used within the driver and have been removed.

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>