mediawidget.h: mark override virtual functions as such
Clang complains about several functions that are overriding
virtual functions from Qt, like:
/src/mediawidget.h:204:7: warning: 'keyPressEvent' overrides a member function but is not marked 'override' [-Winconsistent-missing-override]
15:53:45 void keyPressEvent(QKeyEvent *event);
Mark those functions as such, in order to get rid of the
warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>