MLK-14970-4 imx8qxp_arm2: Add i.MX8QXP ARM2 board support

MLK-14970-4 imx8qxp_arm2: Add i.MX8QXP ARM2 board support

Add board level codes and DTS for i.MX8QXP LPDDR4 ARM2 board.

Copy the DTS from imx_4.9.y kernel on commit:
"4590bca4a6bc6ae8625c37bb027697a17d1b925f"
With modifications to support FlexSPI flash, PCA953x and MIPI I2C.

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

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

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

- Board defconfigs:
  imx8qxp_lpddr4_arm2_defconfig

Signed-off-by: Ranjani Vaidyanathan <Ranjani.Vaidyanathan@nxp.com>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Han Xu <han.xu@nxp.com>
Signed-off-by: Prabhu Sundararaj <prabhu.sundararaj@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>