ath9k: enable serialize_regmode for non-PCIE AR9287

https://bugzilla.kernel.org/show_bug.cgi?id=42903

Based on the work of <fynivx@gmail.com>
Signed-off-by: NPanayiotis Karabassis <panayk@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

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

@@ -622,7 +622,7 @@ static int __ath9k_hw_init(struct ath_hw *ah)
 
 	if (NR_CPUS > 1 && ah->config.serialize_regmode == SER_REG_MODE_AUTO) {
 		if (ah->hw_version.macVersion == AR_SREV_VERSION_5416_PCI ||
-		    ((AR_SREV_9160(ah) || AR_SREV_9280(ah)) &&
+		    ((AR_SREV_9160(ah) || AR_SREV_9280(ah) || AR_SREV_9287(ah)) &&
 		     !ah->is_pciexpress)) {
 			ah->config.serialize_regmode =
 				SER_REG_MODE_ON;