staging: erofs: update erofs-utils information in TODO

erofs-utils was released by the original author Li Guifu
weeks ago in the linux-erofs mailing list [1], update
information in TODO and let's wait the original author
finish all open source works.

[1] https://lists.ozlabs.org/pipermail/linux-erofs/2018-November/001004.html



Cc: Li Guifu <bluce.liguifu@huawei.com>
Cc: Fang Wei <fangwei1@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>