media: vb2: add cross references at memops and v4l2 kernel-doc markups

Add cross-references where needed and add periods at the end of
each kernel-doc paragraph, in order to make it coherent with other
VB2 descriptions.

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/include/media/videobuf2-memops.h b/include/media/videobuf2-memops.h
index a6ed091..4b5b84f 100644
--- a/include/media/videobuf2-memops.h
+++ b/include/media/videobuf2-memops.h
@@ -19,11 +19,11 @@
 #include <linux/refcount.h>
 
 /**
- * struct vb2_vmarea_handler - common vma refcount tracking handler
+ * struct vb2_vmarea_handler - common vma refcount tracking handler.
  *
- * @refcount:	pointer to refcount entry in the buffer
- * @put:	callback to function that decreases buffer refcount
- * @arg:	argument for @put callback
+ * @refcount:	pointer to &refcount_t entry in the buffer.
+ * @put:	callback to function that decreases buffer refcount.
+ * @arg:	argument for @put callback.
  */
 struct vb2_vmarea_handler {
 	refcount_t		*refcount;