This commit adds device tree support for the NXP S32G3-based
S32G-VNP-RDB3 Board [1].

The S32G3 features an 8-core ARM Cortex-A53 based SoC developed by NXP.

The device tree files are derived from the official NXP downstream
Linux tree [2].

This addition encompasses a limited selection of peripherals that
are upstream-supported. Apart from the ARM System Modules
(GIC, Generic Timer, etc.), the following IPs have been validated:

    * UART: fsl-linflexuart
    * SDHC: fsl-imx-esdhc

Clock settings for the chip rely on ATF Firmware [3].
Pin control integration into the device tree is pending and currently
relies on Firmware/U-Boot settings [4].

These changes were validated using BSP39 Firmware/U-Boot from NXP [5].

The modifications enable booting the official Ubuntu 22.04 from NXP on
the RDB3 with default settings from the SD card and eMMC.

[1] https://www.nxp.com/design/design-center/designs/s32g3-vehicle-networking-reference-design:S32G-VNP-RDB3
[2] https://github.com/nxp-auto-linux/linux
[3] https://github.com/nxp-auto-linux/arm-trusted-firmware
[4] https://github.com/nxp-auto-linux/u-boot
[5] https://github.com/nxp-auto-linux/auto_yocto_bspSigned-off-by: Wadim Mueller <wafgo01@gmail.com>
Tested-by: Ghennadi Procopciuc <ghennadi.procopciuc@oss.nxp.com>
Reviewed-by: Ghennadi Procopciuc <ghennadi.procopciuc@oss.nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>