nl80211: add testmode to the list of supported commands

User space might want to test if driver supports testmode. Adding testmode
to the list of supported commands makes this easier.

I omitted testmode_dump() in purpose. I assume all drivers implementing
testmode_dump() will also implement testmode_cmd().

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 50482e1..ae8ea38 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -904,6 +904,10 @@
 		NLA_PUT_U32(msg, i, NL80211_CMD_REGISTER_BEACONS);
 	}
 
+#ifdef CONFIG_NL80211_TESTMODE
+	CMD(testmode_cmd, TESTMODE);
+#endif
+
 #undef CMD
 
 	if (dev->ops->connect || dev->ops->auth) {