directfb: Stop using a packagegroup to fix Vivante GPU runtime dependency
The runtime dependency against libvivante-dfb-mx6 should be specified
in the directfb main package, not in the packagegroup so there is no
risk of it not being right in a customer image.
The other benefit in doing this rework is that the DirectFB 1.7.4
version recipe has no changes and can be immediately removed once
Freescale upgrades the Vivante GPU bindings for DirectFB 1.7.7
support.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
