kbuild,setlocalversion: shorten the make time when using svn

Don't bother doing `svn st` as it takes a retarded amount of time when
the source is cold

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>