staging: bcm2835-audio: propagate PTR_ERR value instead of -EPERM

It is better to propagate PTR_ERR value instead of a hardcoded value
(-EPERM here)
Signed-off-by: NAishwarya Pant <aishpant@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c

@@ -436,7 +436,7 @@ static int bcm2835_audio_open_connection(struct bcm2835_alsa_stream *alsa_stream
 	if (IS_ERR(instance)) {
 		LOG_ERR("%s: failed to initialize audio service\n", __func__);
 
-		ret = -EPERM;
+		ret = PTR_ERR(instance);
 		goto err_free_mem;
 	}