[PATCH][RESEND]saa7134-video.c: fix the block bug

["figo.zhang" <figo.zhang@kolorific.com>]

when re-open or re-start (video_streamon), the q->curr would not be NULL in saa7134_buffer_queue(),
and all the qbuf will add to q->queue list,no one to do activate to start DMA,and then no interrupt 
would happened,so it will be block. 

In VIDEOBUF_NEEDS_INIT state , initial the curr pointer to be NULL in  the buffer_prepare() function.

Signed-off-by: Figo.zhang <figo.zhang@kolorific.com>
---
 drivers/media/video/saa7134/saa7134-video.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/saa7134/saa7134-video.c b/drivers/media/video/saa7134/saa7134-video.c
index 493cad9..550d6ce 100644
--- a/drivers/media/video/saa7134/saa7134-video.c
+++ b/drivers/media/video/saa7134/saa7134-video.c
@@ -1057,6 +1057,7 @@ static int buffer_prepare(struct videobuf_queue *q,
 		buf->vb.field  = field;
 		buf->fmt       = fh->fmt;
 		buf->pt        = &fh->pt_cap;
+		dev->video_q.curr = NULL;
 
 		err = videobuf_iolock(q,&buf->vb,&dev->ovbuf);
 		if (err)