KVM: arm64: nv: Move system instructions to their own sys_reg_desc array

KVM: arm64: nv: Move system instructions to their own sys_reg_desc array

As NV results in a bunch of system instructions being trapped, it makes
sense to pull the system instructions into their own little array, where
they will eventually be joined by AT, TLBI and a bunch of other CMOs.

Based on an initial patch by Jintack Lim.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-13-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>