ALSA: ad1816a: constify copied structure

The snd_ad1816a_timer_table structure is only copied into
another structure, so make it const.

The opportunity for this change was found using Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Link: https://lore.kernel.org/r/1577864614-5543-2-git-send-email-Julia.Lawall@inria.frSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/ad1816a/ad1816a_lib.c

@@ -409,7 +409,7 @@ static int snd_ad1816a_timer_stop(struct snd_timer *timer)
 	return 0;
 }
 
-static struct snd_timer_hardware snd_ad1816a_timer_table = {
+static const struct snd_timer_hardware snd_ad1816a_timer_table = {
 	.flags =	SNDRV_TIMER_HW_AUTO,
 	.resolution =	10000,
 	.ticks =	65535,