{!! Form::model($evento,['route'=>['eventos.update',$evento->id], 'method'=>'PUT','files'=> true])!!}
@include('eventos.form.editar')
{!! Form::submit('Editar',['class'=>'btn btn-primary']) !!}
{!! Form::close() !!}

public function update($id, Request $request)
{
    $evento = Evento::find($id);
    $evento->fill($request->all());
    $evento->save();
    Session::flash('mensaje','Evento editado Correctamente');
    return Redirect::to('eventos');
}

Route::resource('eventos','EventoController');

FatalThrowableError in EventoController.php line 54:
Type error: Too few arguments to function AppHttpControllersEventoController::update(), 1 passed and exactly 2 expected