Add bounds_file_required field to desc.json

This makes it possible to determine whether a bounds file should be
passed to `tosa_verify` without knowledge of the details for how
different compliance modes work.

Signed-off-by: Ian Tayler Lessa <ian.taylerlessa@arm.com>
Change-Id: I3d7bac764ce13f636c7f82ce4a4aa595d82fb79c