[VETH]: move veth.h to include/linux

Move veth.h from net/ to linux/ since it is a user api, and add it to
user header processing Kbuild.

[ Use header-y as suggested by Sam Ravnborg.  -DaveM ]

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index 9abf5a8..f30fa92 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -153,6 +153,7 @@
 header-y += ultrasound.h
 header-y += un.h
 header-y += utime.h
+header-y += veth.h
 header-y += video_decoder.h
 header-y += video_encoder.h
 header-y += videotext.h