ALSA: hda - Allow calling snd_hdac_i915_*() without actual binding

Add the missing NULL checks so that snd_hdac_i915*() can be called
even after the binding with i915 failed.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/hda/hdac_i915.c

@@ -27,7 +27,7 @@ int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable)
 {
 	struct i915_audio_component *acomp = bus->audio_component;
 
-	if (!acomp->ops)
+	if (!acomp || !acomp->ops)
 		return -ENODEV;
 
 	if (!acomp->ops->codec_wake_override) {
@@ -49,7 +49,7 @@ int snd_hdac_display_power(struct hdac_bus *bus, bool enable)
 {
 	struct i915_audio_component *acomp = bus->audio_component;
 
-	if (!acomp->ops)
+	if (!acomp || !acomp->ops)
 		return -ENODEV;
 
 	dev_dbg(bus->dev, "display power %s\n",
@@ -72,7 +72,7 @@ int snd_hdac_get_display_clk(struct hdac_bus *bus)
 {
 	struct i915_audio_component *acomp = bus->audio_component;
 
-	if (!acomp->ops)
+	if (!acomp || !acomp->ops)
 		return -ENODEV;
 
 	return acomp->ops->get_cdclk_freq(acomp->dev);
@@ -179,8 +179,11 @@ int snd_hdac_i915_exit(struct hdac_bus *bus)
 	struct device *dev = bus->dev;
 	struct i915_audio_component *acomp = bus->audio_component;
 
+	if (!acomp)
+		return 0;
+
 	WARN_ON(bus->i915_power_refcount);
-	if (bus->i915_power_refcount > 0 && acomp && acomp->ops)
+	if (bus->i915_power_refcount > 0 && acomp->ops)
 		acomp->ops->put_power(acomp->dev);
 
 	component_master_del(dev, &hdac_component_master_ops);