[media] videobuf2: Add support for file access mode flags for DMABUF exporting

Currently it is not possible for userspace to map a DMABUF exported buffer
with write permissions. This patch allows to also pass O_RDONLY/O_RDWR when
exporting the buffer, so that userspace may map it with write permissions.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index bd8218b..941055e 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -83,7 +83,7 @@
 struct vb2_mem_ops {
 	void		*(*alloc)(void *alloc_ctx, unsigned long size, gfp_t gfp_flags);
 	void		(*put)(void *buf_priv);
-	struct dma_buf *(*get_dmabuf)(void *buf_priv);
+	struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
 
 	void		*(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
 					unsigned long size, int write);