drm/meson: Add implicit fencing support for primary and overlay planes

drm/meson: Add implicit fencing support for primary and overlay planes

Suggested by Qiang Yu <yuq825@gmail.com> to fix tearing artefacts in the
Kodi GUI.

Suggested-by: Qiang Yu <yuq825@gmail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
[narmstrong: added Suggested-by tag]
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1542621759-26413-1-git-send-email-koen@dominion.thruhere.net