KVM: arm64: Compute synthetic sysreg ESR for Apple PMUv3 traps

KVM: arm64: Compute synthetic sysreg ESR for Apple PMUv3 traps

Apple M* CPUs provide an IMPDEF trap for PMUv3 sysregs, where ESR_EL2.EC
is a reserved value (0x3F) and a sysreg-like ISS is reported in
AFSR1_EL2.

Compute a synthetic ESR for these PMUv3 traps, giving the illusion of
something architectural to the rest of KVM.

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-10-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>