egl-helpers: Change file licensing to LGPLv2

The relicense permits sharing the code with Spice which
is LGPL.

All people listed below have agreed to the
relicense:
- Arei Gonglei;
- Cole Robinson;
- Gerd Hoffmann;
- Peter Maydell.
Signed-off-by: NFrediano Ziglio <fziglio@redhat.com>
Acked-by: NCole Robinson <crobinso@redhat.com>
Acked-by: NGonglei <arei.gonglei@huawei.com>
Acked-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 20161208104539.3045-1-fziglio@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

ui/egl-helpers.c

+/*
+ * Copyright (C) 2015-2016 Gerd Hoffmann <kraxel@redhat.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
 #include "qemu/osdep.h"
 #include <glob.h>
 #include <dirent.h>