qtbase: avoid qmake errors due to missing oe-device-extra.pri
qtbase: avoid qmake errors due to missing oe-device-extra.pri

An empty oe-extra-extra.pri file is created if it does not exist to
suppress qmake errors.

Signed-off-by: Jonathan Liu <44960b6aa03eb2fb89c62409a43f0b56d13ff84f@gmail.com>
Signed-off-by: Martin Jansa <516df3ff67e1fa5d153800b15fb204c0a1a389dc@gmail.com>

timopulkkinen/meta-qt5,meta-qt5/meta-qt5,opendreambox/meta-qt5,opendreambox/meta-qt5,schnitzeltony/meta-qt5,kraj/meta-qt5,timopulkkinen/meta-qt5,timopulkkinen/meta-qt5,timopulkkinen/meta-qt5,kraj/meta-qt5,schnitzeltony/meta-qt5,sapiippo/meta-qt5,opendreambox/meta-qt5,sapiippo/meta-qt5,meta-qt5/meta-qt5