dsp: Add afe_close in locked context

Process port command DEVICE_STOP with
afe_cmd_lock to avoid any race condition.

Change-Id: I6e888a70e439cb6f3408d00644fb98a85ae53ef4
Signed-off-by: Soumya Managoli <smanag@codeaurora.org>

dsp/q6afe.c

@@ -7463,6 +7463,7 @@ int afe_close(int port_id)
 		pr_debug("%s: Not a MAD port\n", __func__);
 	}
 
+	mutex_lock(&this_afe.afe_cmd_lock);
 	port_index = afe_get_port_index(port_id);
 	if ((port_index >= 0) && (port_index < AFE_MAX_PORTS)) {
 		this_afe.afe_sample_rates[port_index] = 0;
@@ -7505,6 +7506,7 @@ int afe_close(int port_id)
 		pr_err("%s: AFE close failed %d\n", __func__, ret);
 
 fail_cmd:
+	mutex_unlock(&this_afe.afe_cmd_lock);
 	return ret;
 }
 EXPORT_SYMBOL(afe_close);