drm: Fix link-status kerneldoc line lengths

I'm adding some stuff below it and it's killing my editor's vibe.

Changes in v2:
- Added to the series
Changes in v3:
- None
Changes in v4:
- None
Changes in v5:
- None
Changes in v6:
- None

Cc: Manasi Navare <manasi.d.navare@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180108195545.218615-2-seanpaul@chromium.org