ath9k_hw: fix fast clock handling for 5GHz channels

Combine multiple checks that were supposed to check for the same
conditions, but didn't. Always enable fast PLL clock on AR9280 2.0

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_phy.c b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
index bf8ec68..806f4a5 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
@@ -583,7 +583,7 @@
 	 * For 5GHz channels requiring Fast Clock, apply
 	 * different modal values.
 	 */
-	if (IS_CHAN_A_5MHZ_SPACED(chan))
+	if (IS_CHAN_A_FAST_CLOCK(ah, chan))
 		REG_WRITE_ARRAY(&ah->iniModesAdditional,
 				modesIndex, regWrites);
 
@@ -613,7 +613,7 @@
 	rfMode |= (IS_CHAN_B(chan) || IS_CHAN_G(chan))
 		? AR_PHY_MODE_DYNAMIC : AR_PHY_MODE_OFDM;
 
-	if (IS_CHAN_A_5MHZ_SPACED(chan))
+	if (IS_CHAN_A_FAST_CLOCK(ah, chan))
 		rfMode |= (AR_PHY_MODE_DYNAMIC | AR_PHY_MODE_DYN_CCK_DISABLE);
 
 	REG_WRITE(ah, AR_PHY_MODE, rfMode);