ARM: rmobile: Enable sysinfo on R-Car Gen3

Enable support for sysinfo on supported R-Car Gen3 boards. The sysinfo
is used e.g. to access and decode board-specific information and then
in turn used by board-info to print those information. On R-Car Gen3
the sysinfo rcar3 driver is used to parse the board ID EEPROM, obtain
board type and revision from it, and let board-info print this
information on boot.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>