arm/gic: support injecting IRQs even to VCPUs not currently running

arm/gic: support injecting IRQs even to VCPUs not currently running

The lr_pending list belongs to the vgic rather than the gic, so move it
there.

gic_set_guest_irq should take into account whether the vcpu is currently
running and if it is not it should add the irq to the right lr_pending
list.

When restoring the gic state we need to go through the lr_pending list
because it is possible that some irqs have been "injected" while the
vcpu wasn't running.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>