arm/arm64: KVM: Implement PSCI 1.0 support

From: Marc Zyngier <marc.zyngier@arm.com>

commit 58e0b2239a4d997094ba63986ef4de29ddc91d87 upstream.

PSCI 1.0 can be trivially implemented by providing the FEATURES
call on top of PSCI 0.2 and returning 1.0 as the PSCI version.

We happily ignore everything else, as they are either optional or
are clarifications that do not require any additional change.

PSCI 1.0 is now the default until we decide to add a userspace
selection API.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[v4.9: account for files moved to virt/ upstream]
Signed-off-by: Mark Rutland <mark.rutland@arm.com> [v4.9 backport]
Tested-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>