git-svn (and git) doesn't handle empty directories, so add .empty files
to those dirs like elsewhere in buildroot.
Those empty directories are normally not a big deal, but the recent changes
to u-boot broke the build.
msh is currently the only good choice for uClinux but it doesn't
understands shell functions. In this case there is nothing to gain
by using shell functions anyway.
Signed-off-by: Nicolas Pitre <nico@cam.org>
