i965/drm: Add stall warnings when mapping or waiting on BOs.

i965/drm: Add stall warnings when mapping or waiting on BOs.

This restores the performance warnings removed in:

    i965: Drop brw_bo_map[_gtt] wrappers which issue perf warnings.

but adds them for nearly all BO mapping, and also for wait_rendering.

Because we add this to the core bufmgr, we automatically get stall
warnings in all callers, unlike before where only a few callsites used
the wrappers that gave stall warnings.

We also do it a bit differently: we simply measure how long set_domain
takes (the part that stalls), and complain if it's more than 0.01 ms.
We don't bother calling brw_bo_busy(), and we don't measure the mmap
time (which doesn't stall).  This should be more accurate.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>