staging: use videobuf2 framework for drivers/staging/dt3155v4l driver

This patch transforms drivers/staging/dt3155v4l driver to use videobuf2 framework.
Tested and works with "xawtv -f".

Either streaming API or read method should be selected during kernel configuration.

If both are selected into the driver (not possible without another patching),
either due to my misunderstanding or problems in xawtv (or both), I get kernel panic
after some start/stop of xawtv (not strictly reproducible).

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

drivers/staging/dt3155v4l/Kconfig

@@ -1,7 +1,7 @@
 config VIDEO_DT3155
 	tristate "DT3155 frame grabber, Video4Linux interface"
 	depends on PCI && VIDEO_DEV && VIDEO_V4L2
-	select VIDEOBUF_DMA_CONTIG
+	select VIDEOBUF2_DMA_CONTIG
 	default n
 	---help---
 	  Enables dt3155 device driver for the DataTranslation DT3155 frame grabber.
@@ -18,3 +18,11 @@ config DT3155_CCIR
 	---help---
 	  Select it for CCIR/50Hz (European region),
 	  or leave it unselected for RS-170/60Hz (North America).
+
+config DT3155_STREAMING
+	bool "Selects streaming capture method"
+	depends on VIDEO_DT3155
+	default y
+	---help---
+	  Select it if you want to use streaming of memory mapped buffers
+	  or leave it unselected if you want to use read method (one copy more).