arm:goni:pmic: Adjust GONI target platform board to new PMIC framework

Move pmic_init() function call from board_init() to power_init_board()
to work with new PMIC/POWER framework.

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>