MIPS: Add Mobileye EyeQ6Lplus SoC dtsi

MIPS: Add Mobileye EyeQ6Lplus SoC dtsi

Add the device tree include files for the EyeQ6Lplus system on chip
from Mobileye.

Those files provide the initial support of the SoC:
* The I6500 CPU and GIC interrupt controller.
* The OLB ("Other Logic Block") providing clocks, resets and pin controls.
* One UART.
* One GPIO controller.
* Two SPI controllers, one in host mode and one in target mode.
* One octoSPI flash controller.
* Two I2C controllers.

Signed-off-by: Benoît Monin <benoit.monin@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>