r600g: add htile support v16

r600g: add htile support v16

htile is used for HiZ and HiS support and fast Z/S clears.
This commit just adds the htile setup and Fast Z clear.
We don't take full advantage of HiS with that patch.

v2 really use fast clear, still random issue with some tiles
   need to try more flush combination, fix depth/stencil
   texture decompression
v3 fix random issue on r6xx/r7xx
v4 rebase on top of lastest mesa, disable CB export when clearing
   htile surface to avoid wasting bandwidth
v5 resummarize htile surface when uploading z value. Fix z/stencil
   decompression, the custom blitter with custom dsa is no longer
   needed.
v6 Reorganize render control/override update mecanism, fixing more
   issues in the process.
v7 Add nop after depth surface base update to work around some htile
   flushing issue. For htile to 8x8 on r6xx/r7xx as other combination
   have issue. Do not enable hyperz when flushing/uncompressing
   depth buffer.
v8 Fix htile surface, preload and prefetch setup. Only set preload
   and prefetch on htile surface clear like fglrx. Record depth
   clear value per level. Support several level for the htile
   surface. First depth clear can't be a fast clear.
v9 Fix comments, properly account new register in emit function,
   disable fast zclear if clearing different layer of texture
   array to different value
v10 Disable hyperz for texture array making test simpler. Force
    db_misc_state update when no depth buffer is bound. Remove
    unused variable, rename depth_clearstencil to depth_clear.
    Don't allocate htile surface for flushed depth. Something
    broken the cliprect change, this need to be investigated.
v11 Rebase on top of newer mesa
v12 Rebase on top of newer mesa
v13 Rebase on top of newer mesa, htile surface need to be initialized
    to zero, somehow special casing first clear to not use fast clear
    and thus initialize the htile surface with proper value does not
    work in all case.
v14 Use resource not texture for htile buffer make the htile buffer
    size computation easier and simpler. Disable preload on evergreen
    as its still troublesome in some case
v15 Cleanup some comment and remove some left over
v16 Define name for bit 20 of CP_COHER_CNTL

Signed-off-by: Pierre-Eric Pelloux-Prayer <pelloux@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>