drm/nouveau/kms: restore fbcon after display has been resumed

Under some complicated circumstances (boot, suspend, resume, attach
second display, suspend, resume, suspend, detach second display,
resume, suspend, attach second display, resume), the fb_set_suspend()
call can somehow result in a modeset being attempted before we're
ready for it and things blow up in fun ways.

Running display init first fixes the issue.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>