[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/control.h b/include/sound/control.h
index f1361d6..72e759f 100644
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -49,7 +49,7 @@
 	snd_kcontrol_put_t *put;
 	union {
 		snd_kcontrol_tlv_rw_t *c;
-		unsigned int *p;
+		const unsigned int *p;
 	} tlv;
 	unsigned long private_value;
 };
@@ -69,7 +69,7 @@
 	snd_kcontrol_put_t *put;
 	union {
 		snd_kcontrol_tlv_rw_t *c;
-		unsigned int *p;
+		const unsigned int *p;
 	} tlv;
 	unsigned long private_value;
 	void *private_data;