Merge tag 'topic/mst-bw-check-fixes-for-airlied-2020-03-12-2' of git://anongit.freede...

UAPI Changes: None

Cross-subsystem Changes: None

Core Changes: Fixed regressions introduced by commit 1b05a0166e9b
("drm/dp_mst: Add branch bandwidth validation to MST atomic check"),
which would cause us to:

* Calculate the available bandwidth on an MST topology incorrectly, and
  as a result reject most display configurations that would try to enable
  more then one sink on a topology
* Occasionally expose MST connectors to userspace before finishing
  probing their PBN capabilities, resulting in us rejecting display
  configurations because we assumed briefly that no bandwidth was
  available

Driver Changes: None

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/bf16ee577567beed91c86b7d9cda3ec2e8c50a71.camel@redhat.com