KVM: arm64: nv: Add sanitising to VNCR-backed HCRX_EL2

Just like its little friends, HCRX_EL2 gets the feature set treatment
when backed by VNCR.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-7-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>