KVM: ARM: vgic: move underflow handling to vgic_ops

Move the code dealing with LR underflow handling to its own functions,
and make them accessible through vgic_ops.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --cc include/kvm/arm_vgic.h
Simple merge

diff --cc virt/kvm/arm/vgic.c
Simple merge