staging: dt3155v4l syncronize with API changes

dt3155v4l driver, as in -rc6-next-20100506 compiles, but will
not run properly due to recent changes in the videobuf APIs.

This patch synchronizes some functions that have been copied
from drivers/media/video/videobuf-dma-contig.c (and modified)
with the recent (-rc6 -> -rc6-next-) changes in videobuf layer
especially drivers/media/video/videobuf-dma-contig.c

Signed-off-by: Marin Mitov <mitov@issp.bas.bg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>