ALSA: ASoC: Convert wm8900 to a new-style i2c driver

Convert the wm8900 codec driver to the new (standard) device driver
binding model.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>