KVM: arm64: nv: Use guest hypervisor's vSError state

KVM: arm64: nv: Use guest hypervisor's vSError state

When HCR_EL2.AMO is set, physical SErrors are routed to EL2 and virtual
SError injection is enabled for EL1. Conceptually treating
host-initiated SErrors as 'physical', this means we can delegate control
of the vSError injection context to the guest hypervisor when nesting &&
AMO is set.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-9-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>