UAPI: (Scripted) Disintegrate include/xen

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>

include/uapi/xen/Kbuild

 # UAPI Header export list
+header-y += evtchn.h
+header-y += privcmd.h

include/xen/Kbuild

-header-y += evtchn.h
-header-y += privcmd.h