KVM: arm64: Mask out non-VA bits from TLBI VA* on VNCR invalidation

When handling a TLBI VA* instruction that potentially targets a
VNCR page mapping, we fail to mask out the top bits that contain
the ASID and TTL fields, hence potentially failing the VA check
in the TLB code.

An additional wrinkle is that we fail to sign extend the VA,
again leading to failed VA checks.

Fix both in one go by sign-extending the VA from bit 48, making
it comparable to the way we interpret VNCR_EL2.BADDR.

Fixes: 4ffa72ad ("KVM: arm64: nv: Add S1 TLB invalidation primitive for VNCR_EL2")
Link: https://lore.kernel.org/r/20250525175759.780891-1-maz@kernel.org


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