KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes

KVM: arm64: ptdump: Don't test PTE_VALID alongside other attributes

The attribute masks and test values in the ptdump code are meant for
individual attributes, however for stage-2 ptdump we included PTE_VALID
while testing for R, W, X, and AF. This led to some confusion and the
flipped output for the executable attribute.

Remove PTE_VALID from all attribute masks and values so that each test
matches only the relevant bits.

Additionally, the executable attribute printing is updated to align with
stage-1 ptdump, printing "NX" for non-executable regions and "x " for
executable ones.

Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Suggested-by: Sebastian Ene <sebastianene@google.com>
Signed-off-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>