ath9k: Fix RTC reset delay

The delay that is required after issuing a RTC reset
varies for each chip. Handle this properly.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 2800914..3ca682f 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1363,7 +1363,12 @@
 
 	REGWRITE_BUFFER_FLUSH(ah);
 
-	udelay(50);
+	if (AR_SREV_9300_20_OR_LATER(ah))
+		udelay(50);
+	else if (AR_SREV_9100(ah))
+		udelay(10000);
+	else
+		udelay(100);
 
 	REG_WRITE(ah, AR_RTC_RC, 0);
 	if (!ath9k_hw_wait(ah, AR_RTC_RC, AR_RTC_RC_M, 0, AH_WAIT_TIMEOUT)) {