dt-bindings: display: bridge: lt8912b: Add power supplies

Add Lontium lt8912b power supplies.
Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231115121338.22959-3-francesco@dolcini.it

Documentation/devicetree/bindings/display/bridge/lontium,lt8912b.yaml

@@ -55,6 +55,27 @@ properties:
       - port@0
       - port@1
 
+  vcchdmipll-supply:
+    description: A 1.8V supply that powers the HDMI PLL.
+
+  vcchdmitx-supply:
+    description: A 1.8V supply that powers the HDMI TX part.
+
+  vcclvdspll-supply:
+    description: A 1.8V supply that powers the LVDS PLL.
+
+  vcclvdstx-supply:
+    description: A 1.8V supply that powers the LVDS TX part.
+
+  vccmipirx-supply:
+    description: A 1.8V supply that powers the MIPI RX part.
+
+  vccsysclk-supply:
+    description: A 1.8V supply that powers the SYSCLK.
+
+  vdd-supply:
+    description: A 1.8V supply that powers the digital part.
+
 required:
   - compatible
   - reg