ALSA: ice1712: Add suspend support for M-Audio ICE1712-based cards

Add suspend support for M-Audio cards based on ICE1712 chip.
Tested with M-Audio Audiophile 24/96. S/PDIF will probably not work.

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