texture: remove setInternalFormat

Author: DavidPeicho

src/textures/Texture.js

@@ -300,14 +300,6 @@ Texture.prototype = Object.assign( Object.create( EventDispatcher.prototype ), {
 
 		return uv;
 
-	},
-
-	setInternalFormat: function ( internalFormat ) {
-
-		this.internalFormat = internalFormat;
-
-		return this;
-
 	}
 
 } );