Revert "drm/amd/display: Signal hw_done() after waiting for flip_done()"

This reverts commit 717276b9.

The reverted patch was a workaround that addressed an issue fixed by:
4364bcb2 ("drm: Get ref on CRTC commit object when waiting for
flip_done")

Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>