From: Michael Hunold <hunold@linuxtv.org>

- fix memory leak in page table handling

- minor coding style changes

- add simple resource management for video dmas (borrowed from saa7134)

- use resource management to lock video and vbi access which sometimes
  share the same video dmas

- honour return codes of extension functions in various places, when
  resources could not be locked

- remove remains of dead code which were commented out anyway

- add new flag FORMAT_IS_PLANAR to indicate planar capture formats,
  needed for resource allocation