Textures that are GPU-compressed already (in practice: from DDS files
that are DXT1/DXT3/DXT5 compressed) now can stay GPU compressed
in Vulkan, similar to how that works on OpenGL.
Additionally, fixed lack of mipmaps in Vulkan textures. The textures
were created with mipmaps (good), the sampler too (good), but
the vulkan image view was always saying "yo, this is mip 0 only"
because mip range variables were never set to anything than zero.
Pull Request: https://projects.blender.org/blender/blender/pulls/119866
3663c8147c