KVM: arm64: Don't map 'kvm_vgic_global_state' at EL2 with pKVM

KVM: arm64: Don't map 'kvm_vgic_global_state' at EL2 with pKVM

Now that 'kvm_vgic_global_state' is no longer needed for ICC_CTLR_EL1
emulation on machines with a broken SEIS implementation, drop the
pKVM hypervisor mapping of the page.

Note that kvm_vgic_global_state is still mapped in non-protected
hypervisor configurations (i.e. {n,h}VHE) through the rodata section
mapping.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241022144016.27350-3-will@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>