qcacmn: Fix deadlock due to peer_ref_mutex and scn_lock

Deadlock happens when control path takes scn_lock and calls
dp_peer_unref_delete() which in tern tries to acquire peer_ref_mutex.
At the same time, if other core starts handling peer_unmap by acquiring
peer_ref_mutex and calls dp_reset_and_release_peer_mem() which in turn
calls ol_ath_node_free() and tries to acquire scn_lock leading to a
deadlock.

Fix this by unlocking peer_ref_mutex before calling
dp_reset_and_release_peer_mem().

Change-Id: I343a8ef8f0914f9245a06b2818c9cbbe1db5218f
CRs-Fixed: 2449878

dp/wifi3.0/dp_main.c

@@ -5655,7 +5655,9 @@ void dp_peer_unref_delete(void *peer_handle)
 
 		/* cleanup the peer data */
 		dp_peer_cleanup(vdev, peer);
+		qdf_spin_unlock_bh(&soc->peer_ref_mutex);
 		dp_reset_and_release_peer_mem(soc, pdev, peer, vdev);
+		qdf_spin_lock_bh(&soc->peer_ref_mutex);
 
 		/* check whether the parent vdev has no peers left */
 		if (TAILQ_EMPTY(&vdev->peer_list)) {