KVM: arm64: Rephrase percpu enable/disable tracking in terms of hyp

kvm_arm_hardware_enabled is rather misleading, since it doesn't track
the state of all hardware resources needed for running a VM. What it
actually tracks is whether or not the hyp cpu context has been
initialized.

Since we're now at the point where vgic + timer irq management has
been separated from kvm_arm_hardware_enabled, rephrase it (and the
associated helpers) to make it clear what state is being tracked.

Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230719231855.262973-1-oliver.upton@linux.dev


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>