i965: Resolve framebuffers before signaling the fence

i965: Resolve framebuffers before signaling the fence

From KHR_fence_sync:

  When the condition of the sync object is satisfied by the fence
  command, the sync is signaled by the associated client API context,
  causing any eglClientWaitSyncKHR commands (see below) blocking on
  <sync> to unblock. The only condition currently supported is
  EGL_SYNC_PRIOR_COMMANDS_COMPLETE_KHR, which is satisfied by
  completion of the fence command corresponding to the sync object,
  and all preceding commands in the associated client API context's
  command stream. The sync object will not be signaled until all
  effects from these commands on the client API's internal and
  framebuffer state are fully realized. No other state is affected by
  execution of the fence command.

If clients are passing the fence fd (from EGL_ANDROID_native_fence_sync)
to a compositor, that fence must only be signaled once the framebuffer
is resolved and not before as is currently the case.

v2: fixup assert to use GL_SYNC_GPU_COMMANDS_COMPLETE (Chad)

Reported-by: Sergi Granell <xerpi.g.12@gmail.com>
Fixes: c636284ee8ee ("i965/sync: Implement DRI2_Fence extension")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sergi Granell <xerpi.g.12@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Chad Versace <chadversary@chromium.org>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Chad Versace <chadversary@chromium.org>