MLK-14938-25 imx8qm: Add DTS and binding header files

MLK-14938-25 imx8qm: Add DTS and binding header files

Copy the imx8qm DTS files and its binding header files from imx_4.9.y kernel
on commit:
"
 commit f4b0affd5477301f732efc8ee21185b11495cfcf
 Author: Fugang Duan <fugang.duan@nxp.com>
 Date:   Fri May 19 18:12:23 2017 +0800

    MLK-14952 arm64: dts: imx8qm/qxp: add enet support

    Add enet support for i.MX8QM and i.MX8QXP lpddr4 arm2 board.
"

Add extra support used in u-boot:
1. Add mbox-cells used for mailbox
2. Add alias for FSPI nodes
3. Add GPIO alias which is used as seq number in u-boot DM GPIO driver.
4. Ajust GPIO nodes ahead of i2c nodes. The PCA9557 is a i2c device, if we
   arrange the i2c nodes ahead of GPIO nodes, the GPIO seq number for PCA9557
   will overlay with GPIO nodes. This will cause issue to use GPIO in u-boot.
5. Add i2c alias for i2c0 to i2c4, i2c6 and i2c8.
6. Modify ethernet alias index start from 0

Signed-off-by: Ye Li <ye.li@nxp.com>