dts/sdhc: support mmc dts and usdhc dts

1) dts/bindings/mmc/mmc.yaml: specifies common mmc.

2) dts/bindings/mmc/nxp,imx-usdhc.yaml: specifies
   nxp usdhc module which inherits mmc.

3) dts/arm/nxp/nxp_rt.dtsi: usdhc support on RT chip.

4) boards/arm/mimxrt1050_evk/mimxrt1050_evk.dts:
   usdhc slot support on mimxrt1050_evk board.

Signed-off-by: Jun Yang <jun.yang@nxp.com>
5 files changed