dm: board:samsung: power_init_board: add requirement of CONFIG_DM_PMIC

In the power_init_board function call, regulator driver init is called,
so before compile, make sure that any power framework is defined.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>