power:pmic: prevent data abort for pmic bat command

This patch prevents data abort when pmic bat command is called
on non-batery pmic device.

Signed-off-by: Piotr Wilczek <p.wilczek@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Lukasz Majewski <l.majewski@samsung.com>
CC: Minkyu Kang <mk7.kang@samsung.com>