Add rules for gen_xml and its quiet & silent variants. This causes "make -s"
to be silent for gen_xml.
Signed-off-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>