HE: Disable STBC by default in case of testbed

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
diff --git a/sta.c b/sta.c
index 7ec8e1d..19f2940 100644
--- a/sta.c
+++ b/sta.c
@@ -5544,6 +5544,9 @@
 						ret);
 			}
 #endif /* NL80211_SUPPORT */
+
+			/* Disable STBC as default */
+			wcn_sta_set_stbc(dut, intf, "0");
 		}
 	}
 }