[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>

drivers/net/veth.c

@@ -15,7 +15,7 @@
 
 #include <net/dst.h>
 #include <net/xfrm.h>
-#include <net/veth.h>
+#include <linux/veth.h>
 
 #define DRV_NAME	"veth"
 #define DRV_VERSION	"1.0"

include/linux/Kbuild

@@ -153,6 +153,7 @@ header-y += toshiba.h
 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