MLK-20957-3 ARM64: dts: imx8mm: add eMMC V5.1 support

After fix the ADMA length mismatch issue on imx8mm, we can
support eMMC CMDQ, so enable it. This patch also make imx8mm
support HS400ES mode.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>