Merge branch 'drm-fixes-4.17' of git://people.freedesktop.org/~agd5f/linux into drm...

Two last minute DC fixes for 4.17.  A fix for underscan on fiji and
a fix for gamma settings getting after dpms.

* 'drm-fixes-4.17' of git://people.freedesktop.org/~agd5f/linux:
  drm/amd/display: Update color props when modeset is required
  drm/amd/display: Make atomic-check validate underscan changes