ath9k_hw: remove unnecessary parts of the AR9380 SREV check

Older versions have not been sold and the driver does not explicitly
check for them anyway, so we can simply ignore the macRev here.
Reduces ath9k_hw size on mips by more than 2 KB.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/reg.h

@@ -858,9 +858,7 @@
 #define AR_SREV_9300(_ah) \
 	(((_ah)->hw_version.macVersion == AR_SREV_VERSION_9300))
 #define AR_SREV_9300_20_OR_LATER(_ah) \
-	(((_ah)->hw_version.macVersion > AR_SREV_VERSION_9300) || \
-	 (((_ah)->hw_version.macVersion == AR_SREV_VERSION_9300) && \
-	  ((_ah)->hw_version.macRev >= AR_SREV_REVISION_9300_20)))
+	((_ah)->hw_version.macVersion >= AR_SREV_VERSION_9300)
 
 #define AR_SREV_9485(_ah) \
 	(((_ah)->hw_version.macVersion == AR_SREV_VERSION_9485))