qcacmn: Vendor command support to enable/disable GTX

Add vendor command support to enable or disable GTX.
Currently there is no vendor attribute to enable/disable
GTX from vendor command. Add vendor attribute
QCA_WLAN_VENDOR_ATTR_CONFIG_GTX support through
QCA_NL80211_VENDOR_SUBCMD_SET_WIFI_CONFIGURATION vendor command
and with new wmi command WMI_VDEV_PARAM_GTX_ENABLE.

Change-Id: I8a740f9209ffd5f6438c3cfdd830ee2a76d0aa52
CRs-Fixed: 2261322

os_if/linux/qca_vendor.h

@@ -3403,6 +3403,12 @@ enum qca_wlan_vendor_attr_config {
 	 */
 	QCA_WLAN_VENDOR_ATTR_CONFIG_RSN_IE = 56,
 
+	/*
+	 * 8-bit unsigned value to trigger green Tx power saving.
+	 * 1-Enable, 0-Disable
+	 */
+	QCA_WLAN_VENDOR_ATTR_CONFIG_GTX = 57,
+
 	/* keep last */
 	QCA_WLAN_VENDOR_ATTR_CONFIG_AFTER_LAST,
 	QCA_WLAN_VENDOR_ATTR_CONFIG_MAX =