[Mesa-dev] radeonsi htile (aka HyperZ) support v2

[Andreas Hartmetz]

Performance numbers are still the same.
I've addressed almost all the concerns. Registers that shouldn't be
used when depth htile is disabled are still written anyway because
I figured it's no big overhead, simpler, and possibly safer.
si_texture_htile_alloc_size() is modeled after
si_texture_get_cmask_info() which also has mixed code and declarations,
but well... I've changed it anyway.