amd_iommu: Return int from page walk status helpers

fetch_pte() returns a status code 0 on success, and (small) negative values on failure. The PTE value itself is returned via an output parameter. amdvi_get_top_pt_level_and_perms() follows the same return convention. Both functions currently return uint64_t, which means any negative error values are returned as unsigned and then converted back to int by the callers. This does not cause any issues in the current implementation, but Coverity flags the type mismatch and potential overflow. Make both helpers return int, so the type matches what the return variable is (0 on success, small negative value on failure), and also the type used by all callers to store their return values. No functional changes are intended. Fixes: a1c97c395729 ("amd_iommu: Sync shadow page tables on page invalidation") Fixes: 786550e2d38a ("amd_iommu: Follow root pointer before page walk and use 1-based levels") Reported-by: Peter Maydell <peter.maydell@linaro.org> Suggested-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-ID: <20260630220806.1758748-3-alejandro.j.jimenez@oracle.com>