ALSA: ca0106: Constify snd_ca0106_details

The snd_ca0106_details table entries are referred only as read-only.
Let's make them const.

There should be no functional changes by this patch.

Link: https://lore.kernel.org/r/20200103081714.9560-48-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>