KVM: arm/arm64: vgic: Return error on incompatible uaccess GICD_IIDR writes

KVM: arm/arm64: vgic: Return error on incompatible uaccess GICD_IIDR writes

If userspace attempts to write a GICD_IIDR that does not match the
kernel version, return an error to userspace.  The intention is to allow
implementation changes inside KVM while avoiding silently breaking
migration resulting in guests not running without any clear indication
of what went wrong.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>