intel/blorp: Add a flag to make blorp not re-emit dept/stencil buffers

intel/blorp: Add a flag to make blorp not re-emit dept/stencil buffers

In Vulkan, we want to be able to use blorp to perform clears inside of a
render pass.  If blorp stomps the depth/stencil buffers packets then we'll
have to re-emit them.  This gets tricky when secondary command buffers get
involved.  Instead, we'll simply guarantee that the depth and stencil
buffers we pass to blorp (if any) match those already set in the hardware.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>