boards: meson: add g12a sei510

The SEI510 board is based on the Amlogic S905X2 SoC
from the Amlogic G12A SoC family.

The board has the following specifications :
- Amlogic S905X2 ARM Cortex-A53 quad-core SoC
- XGB DDR4 SDRAM
- 10/100 Ethernet (Internal PHY)
- 1 x USB 3.0 Host
- eMMC
- SDcard
- Infrared receiver
- SDIO WiFi Module

The board default behaviour is for booting Android and triggers
fastboot on recovery or reboot mode.

USB vendor ID (used by fastboot) is 0x18d1 (Google) for
default udev rules for existing android users work out of the box.

Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>