sysinfo: rcar3: Add Renesas R-Car Gen3 sysinfo driver

The Renesas R-Car Gen3 development kits contain board ID EEPROM.
This driver parses out the board ID and revision out of that
EEPROM and exports it e.g. for the board-info print on boot.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Sean Anderson <sean.anderson@seco.com>
Cc: Simon Glass <sjg@chromium.org>