Although in the most platforms, the power of eeprom are alway on, some platforms disable the eeprom power in order to meet low power request. This patch add the pm_runtime ops to control power to support all platforms. Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com> [Bartosz: rebased on top of current at24/for-next] Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>