arm64: dts: freescale: Add NXP S32N79-RDB board support

arm64: dts: freescale: Add NXP S32N79-RDB board support

Add device tree support for the NXP S32N79 Reference Design Board
(RDB) [1].

The S32N79-RDB enables the following peripherals:
- PL011 UART controllers (uart0, uart5, uart6, uart7)
- uSDHC controller
- IRQ steering controller

The board has 32GB of DRAM memory with 28GB usable and 4GB reserved
for ECC logic.

[1] https://www.nxp.com/products/processors-and-microcontrollers/s32-automotive-platform/s32n-vehicle-super-integration-processors:S32N

Co-developed-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Co-developed-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
Signed-off-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>