OMAPDSS: remove ovl/mgr check-code temporarily

DSS currently tries to check that the given overlay and overlay manager
settings are acceptable, but the code does not work quite properly.
Things may change between the check and the actual use of the settings.

Furthermore, the following patches will rewrite how settings are
configured and managed, and trying to keep the (broken) settings
checking working during the rewrite would be very difficult.

This patch removes the checking code, and a working version of checking
will be added back after the settings rewrite has been done.

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