iommu/io-pgtable-arm: Fix IOVA validation for 32-bit

Since we ony support the TTB1 quirk for AArch64 contexts, and
consequently only for 64-bit builds, the sign-extension aspect of the
"are all bits above IAS consistent?" check should implicitly only apply
to 64-bit IOVAs. Change the type of the cast to ensure that 32-bit longs
don't inadvertently get sign-extended, and thus considered invalid, if
they happen to be above 2GB in the TTB0 region.

Reported-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Acked-by: Will Deacon <will@kernel.org>
Fixes: db690301

 ("iommu/io-pgtable-arm: Prepare for TTBR1 usage")
Signed-off-by: Joerg Roedel <jroedel@suse.de>