ath9k_hw: advertise WoW support for capable chipsets

support WoW for all chipsets starting from AR9280, AR9285, AR9287,
AR9380, AR9382, AR9485, AR9462. Really all hardware may not support
WoW even though the flag is set and the WoW working depends on
your laptop, BIOS apart from the hardware.

Cc: Senthil Balasubramanian <senthilb@qca.qualcomm.com>
Cc: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Cc: vadivel@qca.qualcomm.com
Signed-off-by: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -2589,6 +2589,14 @@ int ath9k_hw_fill_cap_info(struct ath_hw *ah)
 	}
 
 
+	if (AR_SREV_9280_20_OR_LATER(ah)) {
+		pCap->hw_caps |= ATH9K_HW_WOW_DEVICE_CAPABLE |
+				 ATH9K_HW_WOW_PATTERN_MATCH_EXACT;
+
+		if (AR_SREV_9280(ah))
+			pCap->hw_caps |= ATH9K_HW_WOW_PATTERN_MATCH_DWORD;
+	}
+
 	return 0;
 }