qt5websockets: correct license info

Fixes http://autobuild.buildroot.net/results/c1d/c1de3b819af574712ec69a99d0db355c6c0ba735/

As stated by README.md:
This code is licensed under LGPL v2.1.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/qt5/qt5websockets/qt5websockets.mk

@@ -11,8 +11,8 @@ QT5WEBSOCKETS_DEPENDENCIES = qt5base
 QT5WEBSOCKETS_INSTALL_STAGING = YES
 
 ifeq ($(BR2_PACKAGE_QT5BASE_LICENSE_APPROVED),y)
-QT5WEBSOCKETS_LICENSE = LGPLv2.1 or GPLv3.0
-QT5WEBSOCKETS_LICENSE_FILES = LICENSE.GPL LICENSE.LGPL LGPL_EXCEPTION.txt
+QT5WEBSOCKETS_LICENSE = LGPLv2.1
+QT5WEBSOCKETS_LICENSE_FILES = LICENSE
 else
 QT5WEBSOCKETS_LICENSE = Commercial license
 QT5WEBSOCKETS_REDISTRIBUTE = NO