ath9k: Set RX filter for Probe Request based on filter flag

This allows mac80211 to enable receiving of Probe Request frames in
station mode which is needed for P2P.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 8656491..bcd3892 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -1739,6 +1739,7 @@
 	FIF_PSPOLL |				\
 	FIF_OTHER_BSS |				\
 	FIF_BCN_PRBRESP_PROMISC |		\
+	FIF_PROBE_REQ |				\
 	FIF_FCSFAIL)
 
 /* FIXME: sc->sc_full_reset ? */