ath9k: use ath9k_hw_write_associd() on reset

Use the already provided helper instead of rewriting the code
required in place.

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/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 227e403..20c1b3e 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -2476,9 +2476,7 @@
 
 	REG_WRITE(ah, AR_DEF_ANTENNA, saveDefAntenna);
 
-	REG_WRITE(ah, AR_BSS_ID0, get_unaligned_le32(sc->curbssid));
-	REG_WRITE(ah, AR_BSS_ID1, get_unaligned_le16(sc->curbssid + 4) |
-		  ((sc->curaid & 0x3fff) << AR_BSS_ID1_AID_S));
+	ath9k_hw_write_associd(ah);
 
 	REG_WRITE(ah, AR_ISR, ~0);