ALSA: ice1712: Add Wolfson Microelectronics WM8776 codec support

Needed by Philips PSC724 subdriver. The code does not contain any
card-specific bits so other ice17xx cards using this codec could be
converted to use this generic code.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>