mac80211: fix WDS channel context test

WDS is (currently) not allowed when channel
contexts are *supported*, not when they're
*not* supported. Fix the inverted test.

Reported-by: Ronald <ronald645@gmail.com>
Tested-by: Ronald <ronald645@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index c42094b..fd8345c 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -751,7 +751,7 @@
 			if (comb->num_different_channels > 1)
 				return -EINVAL;
 		}
-
+	} else {
 		/*
 		 * WDS is currently prohibited when channel contexts are used
 		 * because there's no clear definition of which channel WDS