arm64: renesas: Enable fallback PSCI on Renesas R-Car R8A779G0 V4H White Hawk

arm64: renesas: Enable fallback PSCI on Renesas R-Car R8A779G0 V4H White Hawk

Enable fallback PSCI provider on Renesas R-Car R8A779G0 V4H White Hawk board.

This fallback PSCI provider provides basic PSCI interface which can be used
by the Linux kernel, but does not provide support for bringing up additional
CPU cores or any other functionality, except for SoC level reset.

This fallback PSCI provider is intended as a fallback in case a proper PSCI
provider is not started before the Linux kernel is started. Linux kernel on
ARMv8a will fail to boot in case a PSCI provider is not available, and this
basic fallback PSCI provider assures such a boot failure cannot occur, even
if that means the system will boot in degraded mode with only one CPU core
available, that is still sufficient to perform recovery.

In the common case, a proper PSCI provider should be started as part of
the Linux kernel fitImage, as the BL31 loadable, and replace this basic
fallback PSCI provider before the Linux kernel is started.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>