Remove workaround for Adreno bug (#24611)

src/renderers/shaders/ShaderChunk/normal_fragment_begin.glsl.js

@@ -3,10 +3,8 @@ float faceDirection = gl_FrontFacing ? 1.0 : - 1.0;
 
 #ifdef FLAT_SHADED
 
-	// Workaround for Adreno GPUs not able to do dFdx( vViewPosition )
-
-	vec3 fdx = vec3( dFdx( vViewPosition.x ), dFdx( vViewPosition.y ), dFdx( vViewPosition.z ) );
-	vec3 fdy = vec3( dFdy( vViewPosition.x ), dFdy( vViewPosition.y ), dFdy( vViewPosition.z ) );
+	vec3 fdx = dFdx( vViewPosition );
+	vec3 fdy = dFdy( vViewPosition );
 	vec3 normal = normalize( cross( fdx, fdy ) );
 
 #else