radv: synchronize after performing a separate depth/stencil fast clears

radv: synchronize after performing a separate depth/stencil fast clears

For depth+stencil images, the driver might use an optimized path
if only one aspect is cleared. It either clears the depth or the
stencil part of HTILE. Because the two separate aspects might use
the same HTILE memory we have to synchronize.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>