We can now properly retry at the top level, yay!

v2: Also remove the temporary acquire_ctx hack again, no longer
needed!
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170322215058.8671-6-daniel.vetter@ffwll.ch