ALSA: core: Use standard printk helpers

Use dev_err() & co as much as possible.  If not available (no device
assigned at the calling point), use pr_xxx() helpers instead.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
index 842a97d..6c58e6f 100644
--- a/sound/core/vmaster.c
+++ b/sound/core/vmaster.c
@@ -101,7 +101,7 @@
 	if (slave->info.count > 2  ||
 	    (slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
 	     slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
-		snd_printk(KERN_ERR "invalid slave element\n");
+		pr_err("ALSA: vmaster: invalid slave element\n");
 		kfree(uinfo);
 		return -EINVAL;
 	}