media: video_function_calls.rst: drop obsolete video-set-attributes reference

This fixes this warning:

Documentation/media/uapi/dvb/video_function_calls.rst:9: WARNING: toctree contains
reference to nonexisting document 'uapi/dvb/video-set-attributes'
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/media/uapi/dvb/video_function_calls.rst

@@ -33,4 +33,3 @@ Video Function Calls
     video-clear-buffer
     video-set-streamtype
     video-set-format
-    video-set-attributes