[Mesa-dev] radeonsi htile (aka HyperZ) support

[Andreas Hartmetz]

This adds HyperZ support, without fast clear for now.
I got a lot of help from Marek with this.
There seem to be no piglit regressions; about 60 very basic GL1.0 tests
were skipped in my test run for some reason - they looked very
unrelated. There was no change in other tests.

It does seem to make a difference for performance - running a Xonotic
demo with custom high graphics settings on a Radeon HD 7750 -
Before:
2351 frames 117.2196701 seconds 20.0563608 fps,
 one-second fps min/avg/max: 14 21 28 (75 seconds)
After:
2590 frames 116.1412549 seconds 22.3004306 fps,
 one-second fps min/avg/max: 16 23 30 (82 seconds)