qcacld-3.0: Featurize WEXT support

Add feature flag and featurize WEXT support

Change-Id: I14d2640f66e022faaa38ff6c006dca8485234cf1
CRs-Fixed: 2266697

configs/genoa.snoc.debug_defconfig

@@ -21,6 +21,7 @@ CONFIG_QCA_IBSS_SUPPORT := y
 CONFIG_WLAN_OPEN_P2P_INTERFACE := y
 CONFIG_WLAN_ENABLE_SOCIAL_CHANNELS_5G_ONLY := y
 CONFIG_WLAN_DFS_MASTER_ENABLE := y
+CONFIG_WLAN_WEXT_SUPPORT_ENABLE := y
 CONFIG_WIFI_POS_CONVERGED := y
 CONFIG_WIFI_POS_LEGACY := n
 CONFIG_FEATURE_WLAN_WAPI := y