dts: imx_rt: add pinctrl and gpr for rt1xxx

add dtsi settings for rt series
dtsi use gpr to replace pinmux
nxp iomuxc has gpr which has more settings than mux and io settings
current solution is to export gpr separately and access then directly

Signed-off-by: Hake Huang <hake.huang@oss.nxp.com>
Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>