ath9k_hw: skip WEP aggregation enable code for AR9003

The AR9002 hardware code enables aggregation for WEP but
mac80211 doesn't enable aggregation with WEP, and the AR9003
code family does not need this so skip it for now for AR9003
but leave the code and annotate we should eventually consider
how to remove this in consideration for the HAL unification
goals.

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.h b/drivers/net/wireless/ath/ath9k/hw.h
index e4eacdd..affb848 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -851,6 +851,7 @@
 void ar9002_hw_cck_chan14_spread(struct ath_hw *ah);
 int ar9002_hw_rf_claim(struct ath_hw *ah);
 void ar9002_hw_enable_async_fifo(struct ath_hw *ah);
+void ar9002_hw_enable_wep_aggregation(struct ath_hw *ah);
 
 /*
  * Code specifric to AR9003, we stuff these here to avoid callbacks