OMAPFB: give informative print when probe succeeds

It is quite common to have omapfb probe deferred because of a missing
resource, and to get omapfb probed succesfully a bit later. This works
fine. However, omapfb does not give any print on a successful probe, so
if the omapfb is actually never probed again after deferral, this is not
shown in the log.

To help debugging, add a simple print from omapfb at the end of its
probe, saying which display it is using and in which resolution.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>