overlays: Enable Raspberry Touch 2 rotation with overlay

See: #6480
Signed-off-by: foonerd <foonerd@github.com>

Author: foonerd

arch/arm/boot/dts/overlays/README

@@ -5291,6 +5291,7 @@ Params: sizex                   Touchscreen size x (default 720)
         invy                    Touchscreen inverted y axis
         swapxy                  Touchscreen swapped x y axis
         disable_touch           Disables the touch screen overlay driver
+        rotation                Display rotation {0,90,180,270} (default 0)
         dsi0                    Use DSI0 and i2c_csi_dsi0 (rather than
                                 the default DSI1 and i2c_csi_dsi).
 

arch/arm/boot/dts/overlays/vc4-kms-dsi-ili9881-7inch-overlay.dts

@@ -118,5 +118,6 @@
 		invy = <0>, "+11";
 		swapxy = <&gt911>,"touchscreen-swapped-x-y?";
 		disable_touch = <&gt911>, "status=disabled";
+		rotation = <&dsi_panel>, "rotation:0";
 	};
 };