arm:trats:pmic: Default PMIC(MAX8997) initialization for Samsung's TRATS board

Default PMIC (MAX8997) initialization for Samsung's TRATS development board.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>