mac80211: Do not send mesh HWMP PREQ if HWMP is disabled

When trying to transmit to an unknown destination, the mesh code would
unconditionally transmit a HWMP PREQ even if HWMP is not the current
path selection algorithm.

Signed-off-by: Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
Link: https://lore.kernel.org/r/20200305140409.12204-1-cavallar@lri.fr
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mesh_hwmp.c

@@ -1152,7 +1152,8 @@ int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
 		}
 	}
 
-	if (!(mpath->flags & MESH_PATH_RESOLVING))
+	if (!(mpath->flags & MESH_PATH_RESOLVING) &&
+	    mesh_path_sel_is_hwmp(sdata))
 		mesh_queue_preq(mpath, PREQ_Q_F_START);
 
 	if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)