ALSA: ice1712: Initialize card->private_data properly

Set card->private_data in snd_ice1712_create for fixing NULL
dereference in snd_ice1712_remove().

Signed-off-by: Sean Connor <sconnor004@allyinics.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>