arm: mach-k3: Introduce the basic files to support AM62

arm: mach-k3: Introduce the basic files to support AM62

The AM62 SoC family is the follow on AM335x built on K3 Multicore SoC
architecture platform, providing ultra-low-power modes, dual display,
multi-sensor edge compute, security and other BOM-saving integration.
The AM62 SoC targets broad market to enable applications such as
Industrial HMI, PLC/CNC/Robot control, Medical Equipment, Building
Automation, Appliances and more.

Some highlights of this SoC are:

* Quad-Cortex-A53s (running up to 1.4GHz) in a single cluster.
  Pin-to-pin compatible options for single and quad core are available.
* Cortex-M4F for general-purpose or safety usage.
* Dual display support, providing 24-bit RBG parallel interface and
  OLDI/LVDS-4 Lane x2, up to 200MHz pixel clock support for 2K display
  resolution.
* Selectable GPUsupport, up to 8GFLOPS, providing better user experience
  in 3D graphic display case and Android.
* PRU(Programmable Realtime Unit) support for customized programmable
  interfaces/IOs.
* Integrated Giga-bit Ethernet switch supporting up to a total of two
  external ports (TSN capable).
* 9xUARTs, 5xSPI, 6xI2C, 2xUSB2, 3xCAN-FD, 3x eMMC and SD, GPMC for
  NAND/FPGA connection, OSPI memory controller, 3xMcASP for audio,
  1x CSI-RX-4L for Camera, eCAP/eQEP, ePWM, among other peripherals.
* Dedicated Centralized System Controller for Security, Power, and
  Resource Management.
* Multiple low power modes support, ex: Deep sleep,Standby, MCU-only,
  enabling battery powered system design.

AM625 is the first device of the family. Add DT bindings for the same.

More details can be found in the Technical Reference Manual:
https://www.ti.com/lit/pdf/spruiv7

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Gowtham Tammana <g-tammana@ti.com>
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>