arm/arm64: kvm: drop inappropriate use of kvm_is_mmio_pfn()

arm/arm64: kvm: drop inappropriate use of kvm_is_mmio_pfn()

commit 07a9748c78cfc39b54f06125a216b67b9c8f09ed upstream.

Instead of using kvm_is_mmio_pfn() to decide whether a host region
should be stage 2 mapped with device attributes, add a new static
function kvm_is_device_pfn() that disregards RAM pages with the
reserved bit set, as those should usually not be mapped as device
memory.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>