drm/i915/chv: Add some workaround notes

We implement the following workarounds:
* WaDisableAsyncFlipPerfMode:chv
* WaProgramMiArbOnOffAroundMiSetContext:chv

v2: Drop WaDisableSemaphoreAndSyncFlipWait note

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --cc drivers/gpu/drm/i915/i915_gem_context.c
Simple merge

diff --cc drivers/gpu/drm/i915/intel_ringbuffer.c
Simple merge