[ALSA] Add even more 'const' to everything related to TLV

Mark TLV data as 'const'
Signed-of-by: Philipp Matthias Hahn <pmhahn@pmhahn.de>

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/include/sound/vx_core.h b/include/sound/vx_core.h
index 2173946..4830651 100644
--- a/include/sound/vx_core.h
+++ b/include/sound/vx_core.h
@@ -128,7 +128,7 @@
 	unsigned int num_ins;
 	unsigned int num_outs;
 	unsigned int output_level_max;
-	unsigned int *output_level_db_scale;
+	const unsigned int *output_level_db_scale;
 };
 
 /* hwdep id string */