ath9k_hw: do not recalculate the descriptor checksum in ar9003_hw_fill_txdesc

Reduces the number of accesses to uncached descriptor memory.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ar9003_mac.c b/drivers/net/wireless/ath/ath9k/ar9003_mac.c
index d08ab93..c3179d9 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_mac.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_mac.c
@@ -207,8 +207,7 @@
 	ads->ctl3 &= AR_BufLen;
 
 	/* Fill in pointer checksum and descriptor id */
-	ads->ctl10 = ar9003_calc_ptr_chksum(ads);
-	ads->ctl10 |= (descid << AR_TxDescId_S);
+	ads->ctl10 = (descid << AR_TxDescId_S);
 
 	if (is_firstseg) {
 		ads->ctl12 |= (is_lastseg ? 0 : AR_TxMore);