Don't build empty built-in.o when DVB/V4L is not configured.  Thanks to Sam
Ravnborg and Keith Owens.
Signed-off-by: NJohannes Stezenbach <js@linuxtv.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>