ALSA: control: Fix missing __user annotation

There is one place missing __user annotation to the pointer used by
the recent code refactoring.  Reported by sparse.

Fixes: 450296f3 ("ALSA: control: code refactoring TLV ioctl handler")
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/control.c

@@ -1492,7 +1492,7 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
                              int op_flag)
 {
 	struct snd_ctl_tlv header;
-	unsigned int *container;
+	unsigned int __user *container;
 	unsigned int container_size;
 	struct snd_kcontrol *kctl;
 	struct snd_ctl_elem_id id;