dtoverlays: Add link-frequency override to imx477/378 overlay

Copy of the imx708 change.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

Author: 6by9

arch/arm/boot/dts/overlays/README

@@ -2812,6 +2812,8 @@ Params: rotation                Mounting rotation of the camera sensor (0 or
                                 camera clamping I/Os such as XVS to 0V.
         sync-source             Configure as vsync source
         sync-sink               Configure as vsync sink
+        link-frequency          Allowable link frequency values to use in Hz:
+                                450000000 (default), 453000000, 456000000.
 
 
 Name:   imx462
@@ -2854,6 +2856,8 @@ Params: rotation                Mounting rotation of the camera sensor (0 or
                                 camera clamping I/Os such as XVS to 0V.
         sync-source             Configure as vsync source
         sync-sink               Configure as vsync sink
+        link-frequency          Allowable link frequency values to use in Hz:
+                                450000000 (default), 453000000, 456000000.
 
 
 Name:   imx500

arch/arm/boot/dts/overlays/imx477_378-overlay.dtsi

@@ -86,6 +86,7 @@
 		       <&cam_node>, "clocks:0=",<&cam0_clk>,
 		       <&cam_node>, "VANA-supply:0=",<&cam0_reg>;
 		always-on = <0>, "+99";
+		link-frequency = <&cam_endpoint>,"link-frequencies#0";
 	};
 };