dsp: address deadlock situation in prm driver during subsystem restart

When ADSP crashes, prm driver can get audio PD down notification from
audio notifier in one thread while prm device instance is being removed
in another thread. This leads to two threads acquiring two locks
(audio notifier & prm) in reverse order. Update audio_prm_remove function
to deregister audio_notifier without acquiring prm lock.

Change-Id: I76dda54340973dc8c4005c741b273dfbdbb1610d
Signed-off-by: Patrick Lai <[email protected]>

dsp/audio_prm.c

@@ -370,10 +370,10 @@ static int audio_prm_remove(struct gpr_device *adev)
 {
 	int ret = 0;
 
+	audio_notifier_deregister("audio_prm");
 	mutex_lock(&g_prm.lock);
 	g_prm.is_adsp_up = false;
 	g_prm.adev = NULL;
-	audio_notifier_deregister("audio_prm");
 	mutex_unlock(&g_prm.lock);
 	return ret;
 }