dma-buf/sync_file: fix documentation error

The ioctl name and description on the documentation block don't
match the ioctl being defined. This was probably overlooked while
renaming the ioctls during the sync file destaging. This patch
provides a more accurate description of what the ioctl actually does.
Signed-off-by: Emilio López <emilio.lopez@collabora.co.uk>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20160919042120.6280-1-emilio.lopez@collabora.co.uk

include/uapi/linux/sync_file.h

@@ -85,15 +85,12 @@ struct sync_file_info {
 #define SYNC_IOC_MERGE		_IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data)
 
 /**
- * DOC: SYNC_IOC_FENCE_INFO - get detailed information on a fence
+ * DOC: SYNC_IOC_FILE_INFO - get detailed information on a sync_file
  *
- * Takes a struct sync_file_info_data with extra space allocated for pt_info.
- * Caller should write the size of the buffer into len.  On return, len is
- * updated to reflect the total size of the sync_file_info_data including
- * pt_info.
- *
- * pt_info is a buffer containing sync_pt_infos for every sync_pt in the fence.
- * To iterate over the sync_pt_infos, use the sync_pt_info.len field.
+ * Takes a struct sync_file_info. If num_fences is 0, the field is updated
+ * with the actual number of fences. If num_fences is > 0, the system will
+ * use the pointer provided on sync_fence_info to return up to num_fences of
+ * struct sync_fence_info, with detailed fence information.
  */
 #define SYNC_IOC_FILE_INFO	_IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)