soc: add pinctrl header file definition for RT series

Pinctrl requires header file with Z_PINCTRL_STATE_PINS_INIT macro
defined. Add header file for mcux RT pinctrl implementation.
Signed-off-by: Hake Huang <hake.huang@oss.nxp.com>
Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>