radeonsi/tmz: allow secure job if the app made a tmz allocation

radeonsi/tmz: allow secure job if the app made a tmz allocation

This commit makes TMZ always allowed instead of being either off or forced-on
with AMD_DEBUG=tmz.

With this change:
- secure job can be used as soon as the application made a tmz allocation. Driver
  internal allocations are not enough to enable secure jobs (if tmz is supported
  and enabled by the kernel)
- AMD_DEBUG=tmz forces all scanout/depth/stencil buffers to be allocated as TMZ.
  This is useful to test app thats don't explicitely support protected content.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6049>