KVM: arm/arm64: Check that system supports split eoi/deactivate

Some systems without proper firmware and/or hardware description data
don't support the split EOI and deactivate operation.

On such systems, we cannot leave the physical interrupt active after the
timer handler on the host has run, so we cannot support KVM with an
in-kernel GIC with the timer changes we are about to introduce.

This patch makes sure that trying to initialize the KVM GIC code will
fail on such systems.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>