KVM: arm64: Move SVCR into the sysreg array

SVCR is just a system register, and has no purpose being outside
of the sysreg array. If anything, it only makes it more difficult
to eventually support SME one day. If ever.

Move it into the array with its little friends, and associate it
with a visibility predicate.

Although this is dead code, it at least paves the way for the
next set of FP-related extensions.

Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240820131802.3547589-2-maz@kernel.org


Signed-off-by: Marc Zyngier <maz@kernel.org>