OMAPDSS: add helpers to get mgr or output from display

Add two helper functions that can be used to find either the DSS output
or the overlay manager that is connected to the given display.

This hides how the output and the manager are actually connected, making
it easier to change the connections in the future.

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