drm/amd/display: Do not set bandwidth on page flips.

Which removes a lockdep warning for a possible deadlock situation:

While holding the drm event mutex (hard irq safe),
dc_post_update_surfaces_to_stream eventually acquires the atom context
lock, which is hard irq unsafe. We should only be calling it on full
updates anyways.

Also remove a redundant call to dc_post_update_surfaces_to_stream,
dc_commit_updates_for_stream already calls it.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>