backend-drm: Use panel orientation connector property
For some devices the kernel knows about the panel mounting orientation. In that case a panel orientation property is added to the connector. Use this property to initialize the output transformation.
This still allows to overwrite the transformation in the weston.ini file, but it should allow some more devices to start with a useful default.
Signed-off-by: Lucas Stach l.stach@pengutronix.de Signed-off-by: Marius Vlad marius.vlad@collabora.com
This merely adapts Lucas's work to latest weston version.