V4L/DVB (7566): videobuf-dvb: allow its usage with videobuf-vmalloc

videobuf-dvb were still using a function that were videobuf-dma-sg
dependent. This patch creates a generic handler for this function. This
way, videobuf-dvb can now work with all videobuf implementations.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/videobuf-dma-sg.c b/drivers/media/video/videobuf-dma-sg.c
index c0b7902..03a7b94 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -432,6 +432,16 @@
 	return vb;
 }
 
+static void *__videobuf_to_vmalloc (struct videobuf_buffer *buf)
+{
+	struct videobuf_dma_sg_memory *mem = buf->priv;
+	BUG_ON(!mem);
+
+	MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+	return mem->dma.vmalloc;
+}
+
 static int __videobuf_iolock (struct videobuf_queue* q,
 			      struct videobuf_buffer *vb,
 			      struct v4l2_framebuffer *fbuf)
@@ -677,6 +687,7 @@
 	.mmap_mapper  = __videobuf_mmap_mapper,
 	.video_copy_to_user = __videobuf_copy_to_user,
 	.copy_stream  = __videobuf_copy_stream,
+	.vmalloc      = __videobuf_to_vmalloc,
 };
 
 void *videobuf_sg_alloc(size_t size)