atheros: define shared bssidmask setting

Also make ath5k and ath9k use it, and share register definitions.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index 13bbf3d..1abbebc 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -593,6 +593,7 @@
 	sc->ah->ah_iobase = sc->iobase;
 	common = ath5k_hw_common(sc->ah);
 	common->ops = &ath5k_common_ops;
+	common->ah = sc->ah;
 	common->cachelsz = csz << 2; /* convert to bytes */
 
 	/* Initialize device */