radeonsi: implement TC-compatible HTILE

radeonsi: implement TC-compatible HTILE

so that decompress blits aren't needed and depth texturing needs less
memory bandwidth.

Z16 and Z24 are promoted to Z32_FLOAT by the driver, because TC-compatible
HTILE only supports Z32_FLOAT. This doubles memory footprint for Z16.
The format promotion is not visible to state trackers.

This is part of TC-compatible renderbuffer compression, which has 3 parts:
DCC, HTILE, FMASK. Only TC-compatible FMASK compression is missing now.

I don't see a measurable increase in performance though.

(I tested Talos Principle and DiRT: Showdown, the latter is improved by
 0.5%, which is almost noise, and it originally used layered Z16,
 so at least we know that Z16 promoted to Z32F isn't slower now)

Tested-by: Edmondo Tommasina <edmondo.tommasina@gmail.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>