ath9k: fix channel frequency calculation for AR9340

A multiplication is missing from the current formula.

Cc: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ar9003_phy.c

@@ -104,7 +104,7 @@ static int ar9003_hw_set_channel(struct ath_hw *ah, struct ath9k_channel *chan)
 			u32 chan_frac;
 
 			channelSel = (freq * 2) / 75;
-			chan_frac = ((freq % 75) * 0x20000) / 75;
+			chan_frac = (((freq * 2) % 75) * 0x20000) / 75;
 			channelSel = (channelSel << 17) | chan_frac;
 		} else {
 			channelSel = CHANSEL_5G(freq);