ALSA: ice1712: More constifications

Apply const prefix to each possible place: the EEPROM tables, the
static string arrays, the init verb tables, etc.

Just for minor optimization and no functional changes.

Link: https://lore.kernel.org/r/20200105144823.29547-17-tiwai@suse.de


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