The last user has been transitioned to walking the LPI xarray directly.
Cut the wart off, and get rid of the now unneeded lpi_count while doing
so.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240422200158.2606761-7-oliver.upton@linux.devSigned-off-by: Marc Zyngier <maz@kernel.org>