KVM: arm64: Save ESR_EL2 on guest SError

KVM: arm64: Save ESR_EL2 on guest SError

BugLink: http://bugs.launchpad.net/bugs/1756096
When we exit a guest due to an SError the vcpu fault info isn't updated
with the ESR. Today this is only done for traps.

The v8.2 RAS Extensions define ISS values for SError. Update the vcpu's
fault_info with the ESR on SError so that handle_exit() can determine
if this was a RAS SError and decode its severity.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit c60590b552bdf682043579b9b965e6224fbf65d9)
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>