KVM: arm64: nv: Move TLBI range decoding to a helper

As we are about to expand out TLB invalidation capabilities to support
recursive virtualisation, move the decoding of a TLBI by range into
a helper that returns the base, the range and the ASID.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250514103501.2225951-6-maz@kernel.org


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