[ALSA] Add SNDRV_PCM_IOCTL_TSTAMP back to compat ioctl

The replaced one should be re-added for older alsa-lib.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index 1fb6ae7..49aa693 100644
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -483,6 +483,7 @@
 	switch (cmd) {
 	case SNDRV_PCM_IOCTL_PVERSION:
 	case SNDRV_PCM_IOCTL_INFO:
+	case SNDRV_PCM_IOCTL_TSTAMP:
 	case SNDRV_PCM_IOCTL_TTSTAMP:
 	case SNDRV_PCM_IOCTL_HWSYNC:
 	case SNDRV_PCM_IOCTL_PREPARE: