KVM: arm64: Drop useless PAN setting on host EL1 to EL2 transition

Setting PSTATE.PAN when entering EL2 on nVHE doesn't make much
sense as this bit only means something for translation regimes
that include EL0. This obviously isn't the case in the nVHE case,
so let's drop this setting.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Link: https://lore.kernel.org/r/20201026095116.72051-4-maz@kernel.org