power_supply: Convert i2c drivers to module_i2c_driver

Factor out some boilerplate code for i2c driver registration
into module_i2c_driver.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Woogyom Kim <milo.kim@ti.com>
Cc: Daniel Jeong <daniel.jeong@ti.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Peter Edwards <sweetlilmre@gmail.com>
Acked-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Acked-by: Rhyland Klein <rklein@nvidia.com>
Acked-by: Ryan Mallon <rmallon@gmail.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>