Fix format aspects validation for DRM format modifier images

[cadubentzen]

1. Update documentation to reflect any user-facing changes - in this repository.

2. Make sure that the changes are covered by unit-tests.

3. Run cargo clippy on the changes.

4. Run cargo +nightly fmt on the changes.

5. Please put changelog entries in the description of this Pull Request
   if knowledge of this change could be valuable to users. No need to put the
   entries to the changelog directly, they will be transferred to the changelog
   file by maintainers right after the Pull Request merge.

   Please remove any items from the template below that are not applicable.

6. Describe in common words what is the purpose of this change, related
   GitHub Issues, and highlight important implementation aspects.

   When calling subresource_layout() on a RawImage that uses DRM format modifiers (ImageTiling::DrmFormatModifier), the validation would fall through into the format-aspects checks after correctly validating the MemoryPlane aspect. This caused spurious validation errors because DRM format modifier images use MemoryPlane aspects, not the usual format aspects (Color, Depth, Stencil, Plane0, etc.).

   The fix adds an extra self.tiling != ImageTiling::DrmFormatModifier around the validation which was previously failing.

Changelog:

### Bugs fixed
- `RawImage::subresource_layout` validation incorrectly rejected valid `MemoryPlane` aspects for DRM format modifier images.

[marc0246]

Thank you! However, an early return in validation is something we don't do. And I wouldn't want to start doing it because it's inevitably going to be overlooked in the future. There even is commented-out validation later down pertaining to DRM format modifier. So instead, please put the other validation later down in an if self.tiling != ImageTiling::DrmFormatModifier block instead.

[cadubentzen]

Thanks for the review! Done.

[marc0246]

Thank you for the fix!