v3dv: implement support for depth testing

This ignores stencil for now and focuses on depth testing without
support for early depth testing.

To implement this we need to start considering how many of our
framebuffer attachments are color attachments, since some of the
computations we use to determine tile sizes and binning configuration
depend on this.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
7 files changed