Use fullpath for validator facade

Added fullpath import for the validator facade.

app/Http/Controllers/Auth/RegisterController.php

@@ -3,8 +3,8 @@
 namespace App\Http\Controllers\Auth;
 
 use App\User;
-use Validator;
 use App\Http\Controllers\Controller;
+use Illuminate\Support\Facades\Validator;
 use Illuminate\Foundation\Auth\RegistersUsers;
 
 class RegisterController extends Controller