runqemu-extract-sdk: allow install debugfs on rootfs
Usually, the debugfs' (-dbg.tar.*) work follow is:
1) Install regular rootfs to dir_foo
2) Install debugfs (-dbg.tar.*) to the same dir_foo
So we need to allow installing the debugfs on top of the rootfs.
Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>