i965: Refactor lossless compression state tracking

i965: Refactor lossless compression state tracking

Essentially this moves fast clear state update away from surface
state setup into brw_postdraw_set_buffers_need_resolve() that gets
called just after draw submission.
Calling intel_miptree_used_for_rendering() can be drop for gen6
and earlier as it is no-op.

v2: Rebased on top current master setting the state in
    blorp_surf_for_miptree().

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