drm/stm: ltdc: add support of horizontal & vertical mirroring

Support of vertical & horizontal mirroring features thanks to
the plane rotation property.

Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
Signed-off-by: Philippe Cornu <philippe.cornu@foss.st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220603134547.593790-1-yannick.fertre@foss.st.com