dt-binding: display: Require two resets on mantix panel

We need to reset both for the panel to show an image.

Fixes: b9ab1248 ("dt-bindings: Add Mantix MLAF057WE51-X panel bindings")
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/15d3dc7eb4e031f380be1298ed3ac9085626f26b.1602584953.git.agx@sigxcpu.org

Documentation/devicetree/bindings/display/panel/mantix,mlaf057we51-x.yaml

@@ -37,6 +37,9 @@ properties:
 
   reset-gpios: true
 
+  'mantix,tp-rstn-gpios':
+    description: second reset line that triggers DSI config load
+
   backlight: true
 
 required:
@@ -63,6 +66,7 @@ examples:
             avee-supply = <&reg_avee>;
             vddi-supply = <&reg_1v8_p>;
             reset-gpios = <&gpio1 29 GPIO_ACTIVE_LOW>;
+            mantix,tp-rstn-gpios = <&gpio1 24 GPIO_ACTIVE_LOW>;
             backlight = <&backlight>;
         };
     };