ASoC: Add __devinit/__devexit annotations at necessary places

Fix below build warning when CONFIG_HOTPLUG is not set.

  CC      sound/soc/codecs/alc5623.o
sound/soc/codecs/alc5623.c:1062: warning: ‘alc5623_i2c_remove’ defined but not used
  CC      sound/soc/codecs/alc5632.o
sound/soc/codecs/alc5632.c:1112: warning: ‘alc5632_i2c_remove’ defined but not used

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Leon Romanovsky <leon@leon.nu>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>