ALSA: hdspm - Fix SNDRV_HDSPM_IOCTL_GET_LTC

Use struct hdspm_ltc to query the LTC, using a mixer struct is just
plain wrong.

Due to the wrong struct, this ioctl was never working, so we're free to
fix it without breaking userspace compatibility.
Signed-off-by: Adrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/uapi/sound/hdspm.h

@@ -111,7 +111,7 @@ struct hdspm_ltc {
 	enum hdspm_ltc_input_format input_format;
 };
 
-#define SNDRV_HDSPM_IOCTL_GET_LTC _IOR('H', 0x46, struct hdspm_mixer_ioctl)
+#define SNDRV_HDSPM_IOCTL_GET_LTC _IOR('H', 0x46, struct hdspm_ltc)
 
 /**
  * The status data reflects the device's current state