wlan:11AC Tx BeamForming Feature support.

Modified the driver to support 11AC Tx Beamforming Feature.

Change-Id: I4e08692f1637261315e41372a5891854a286300c
(cherry picked from commit af6fe6b148f1979b7c821b990a12d956d3cb39a3)
diff --git a/CORE/WDA/inc/legacy/halMsgApi.h b/CORE/WDA/inc/legacy/halMsgApi.h
index d747e2a..599a840 100644
--- a/CORE/WDA/inc/legacy/halMsgApi.h
+++ b/CORE/WDA/inc/legacy/halMsgApi.h
@@ -328,6 +328,7 @@
 #ifdef WLAN_FEATURE_11AC
     tANI_U8    vhtCapable;
     tANI_U8    vhtTxChannelWidthSet;
+    tANI_U8    vhtTxBFCapable;
 #endif
 
     tANI_U8    htLdpcCapable;