ALSA: ac97: fix check of pm_runtime_get_sync failure

pm_runtime_get_sync returns negative on failure.

Fixes: 74426fbff66e ("ALSA: ac97: add an ac97 bus")
Signed-off-by: Lihua Yao <ylhuajnu@163.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/ac97/bus.c

@@ -529,7 +529,7 @@ static int ac97_bus_remove(struct device *dev)
 	int ret;
 
 	ret = pm_runtime_get_sync(dev);
-	if (ret)
+	if (ret < 0)
 		return ret;
 
 	ret = adrv->remove(adev);