ath9k_hw: clean up hardware revision checks

- AR_SREV_5416_20_OR_LATER is always true, remove it
- AR_SREV_9280_20_OR_LATER is always true within eeprom_4k.c and eeprom_9287.c
- (AR_SREV_9271 || AR_SREV_9285) is always true in eeprom_4k.c

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/mac.c b/drivers/net/wireless/ath/ath9k/mac.c
index 786587a..22f23ea 100644
--- a/drivers/net/wireless/ath/ath9k/mac.c
+++ b/drivers/net/wireless/ath/ath9k/mac.c
@@ -584,7 +584,7 @@
 	else
 		rs->rs_keyix = ATH9K_RXKEYIX_INVALID;
 
-	rs->rs_rate = RXSTATUS_RATE(ah, (&ads));
+	rs->rs_rate = MS(ads.ds_rxstatus0, AR_RxRate);
 	rs->rs_more = (ads.ds_rxstatus1 & AR_RxMore) ? 1 : 0;
 
 	rs->rs_isaggr = (ads.ds_rxstatus8 & AR_RxAggr) ? 1 : 0;