board: phytec: am62a7: Add PHYTEC phyCORE-AM62A7 SoM

Add support for PHYTEC phyCORE-AM62A7 SoM.

Supported features:
  - 2GB LPDDR4 RAM
  - eMMC
  - External SD
  - Ethernet
  - debug UART

Signed-off-by: Garrett Giordano <ggiordano@phytec.com>
Reviewed-by: Wadim Egorov <w.egorov@phytec.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Bryan Brattlof <bb@ti.com>
19 files changed