MLK-14938-26 imx8qm_arm2: Add i.MX8QM ARM2 board support

MLK-14938-26 imx8qm_arm2: Add i.MX8QM ARM2 board support

Add board level codes and DTS for i.MX8QM LPDDR4 ARM2 board.

Copy the DTS from imx_4.9.y kernel on commit:
"f4b0affd5477301f732efc8ee21185b11495cfcf"
With modifications to support FlexSPI flash and PCA953x

- Enabled DM driver:
  FEC, LPUART, LPI2C, GPIO, SD/MMC, FSPI, PCA953X

- Enabled Non-DM driver:
  SATA, PCIE, iomux, fuse

- Disabled driver:
  mailbox, pinctrl (will try to use later)

- Board defconfigs:
  imx8qm_lpddr4_arm2_defconfig

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Han Xu <han.xu@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>