drm/sun4i: Add compatible strings for A31/A31s display pipelines

drm/sun4i: Add compatible strings for A31/A31s display pipelines

commit 49c440e87cd6f547f93d0dc53571ae0e11d9ec8f upstream.

The A31's display pipeline has 2 frontends, 2 backends, and 2 TCONs. It
also has new display enhancement blocks, such as the DRC (Dynamic Range
Controller), the DEU (Display Enhancement Unit), and the CMU (Color
Management Unit). It supports HDMI, MIPI DSI, and 2 LCD/LVDS channels.

The A31s display pipeline is almost the same, just without MIPI DSI.
Only the TCON seems to be different, due to the missing mux for MIPI
DSI.

Add compatible strings for both of them.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>