dt-bindings: one file of all simple DSI panels

dt-bindings: one file of all simple DSI panels

To complement panel-simple.yaml, create panel-simple-dsi.yaml.
panel-simple-dsi-yaml are for all simple DSP panels with a single
power-supply and optional backlight / enable GPIO.

Migrate panasonic,vvx10f034n00 over to the new file.

The objectives with one file for all the simple DSI panels are:
    - Make it simpler to add bindings for simple DSI panels
    - Keep the number of bindings file lower
    - Keep the binding documentation for simple DSI panels more consistent

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Yannick Fertre <yannick.fertre@st.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: devicetree@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200206133344.724-2-benjamin.gaignard@st.com