Revert "mwifiex: advertise PS ON by default support to cfg80211"

This reverts upstream commit c2b6680f63f which enables driver to enter
powersave as soon as connected.

Reason: Causes firmware hang with message "Firmware wakeup failed",
and also bluetooth becomes inaccessible.

See b/28425386

Change-Id: If704a863f9f01a38bdff6325cd4faa27524ac55f
diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
index 4431836..83d09ac 100644
--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -3840,8 +3840,7 @@
 			WIPHY_FLAG_AP_PROBE_RESP_OFFLOAD |
 			WIPHY_FLAG_AP_UAPSD |
 			WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL |
-			WIPHY_FLAG_HAS_CHANNEL_SWITCH |
-			WIPHY_FLAG_PS_ON_BY_DEFAULT;
+			WIPHY_FLAG_HAS_CHANNEL_SWITCH;
 
 	if (ISSUPP_TDLS_ENABLED(adapter->fw_cap_info))
 		wiphy->flags |= WIPHY_FLAG_SUPPORTS_TDLS |