staging: brcm80211: provide TSF value in receive status

Packets passed to the mac80211 stack have a mactime field in the
receive status indicating the actual time it was received by the
phy radio. It was not (properly) filled in before this change.

Cc: devel@linuxdriverproject.org
Cc: linux-wireless@vger.kernel.org
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Henry Ptasinski <henryp@broadcom.com>
Cc: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>