package/qt5wayland: examples needs opengl with qt latest

package/qt5wayland: examples needs opengl with qt latest

WIth Qt latest, if opengl is not enabled, qt5wayland examples won't be
built:
make[3]: Entering directory `/home/dawncrow/buildroot-test/scripts/instance-0/output/build/qt5wayland-5.12.2/examples/wayland'
Some of the required modules (qtConfig(opengl)) are not available.
Skipped.
make[3]: Leaving directory `/home/dawncrow/buildroot-test/scripts/instance-0/output/build/qt5wayland-5.12.2/examples/wayland'

And build will fail on:
cp: cannot stat '/home/dawncrow/buildroot-test/scripts/instance-0/output/host/sparc64-buildroot-linux-gnu/sysroot/usr/lib/qt/examples/wayland': No such file or directory

Fixes:
 - http://autobuild.buildroot.org/results/902322ca156c14044d4ce53ab2c77f30dd854c98

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>