ALSA: fix unused warnings with snd_power_get_state

If we compile the ASoC code with PM disabled, we hit stuff like:
sound/soc/soc-dapm.c: In function 'snd_soc_dapm_suspend_check':
sound/soc/soc-dapm.c:440: warning: unused variable 'codec'

So tweak the stub macro to avoid these issues.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/core.h

@@ -179,7 +179,7 @@ int snd_power_wait(struct snd_card *card, unsigned int power_state);
 #define snd_power_lock(card)		do { (void)(card); } while (0)
 #define snd_power_unlock(card)		do { (void)(card); } while (0)
 static inline int snd_power_wait(struct snd_card *card, unsigned int state) { return 0; }
-#define snd_power_get_state(card)	SNDRV_CTL_POWER_D0
+#define snd_power_get_state(card)	({ (void)(card); SNDRV_CTL_POWER_D0; })
 #define snd_power_change_state(card, state)	do { (void)(card); } while (0)
 
 #endif /* CONFIG_PM */