dtoverlays: Use edt-ft5506 for 10 points, instead of edt-ft5x06

Whilst all the datasheets describe FT5x06 as supporting "up to
10 points of absolution X and Y coordinates", the driver
implementation for the compatible string "edt,edt-ft5x06" only
allows for 5.

Switch to the "edt,edt-ft5506" compatible string which allows for
10 points with no other differences.

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

arch/arm/boot/dts/overlays/edt-ft5406.dtsi

@@ -28,7 +28,7 @@
 			#address-cells = <1>;
 			#size-cells = <0>;
 			ft5406: ts@38 {
-				compatible = "edt,edt-ft5406";
+				compatible = "edt,edt-ft5506";
 				reg = <0x38>;
 
 				touchscreen-size-x = < 800 >;