[LTP] [RFC] make mce-test a submodule

[Caspar Z. <ca...@ca...>]

Hi Garrett, Andi, and all:

When I looked into current LTP tree, I found it a little messy due to
some mce-test stuff, such as

  - mce-test docs goes to $TOPDIR/README, and
  - some mce-test files still lying under testcase/mce-test/.

I think we need a cleanup for it.

Also an idea comes to my mind, that we can try to make mce-test a
submodule of LTP.

I am also thinking about the pros and cons:

pro(s):
  - easier for code maintenance, no need to sync periodically from
maintainer side

con(s):
  - two extra steps added for LTP users, they have to do:
    $ git submodule init
    $ git submodule update
to enable using mce-test.

mce-test could no longer be found at kernel.org, so I cloned it from
Andi's github repo, not sure if it is the right place:

    git://github.com/andikleen/mce-test.git

I have made this change to my personal LTP fork, you can review it here:

    https://github.com/casparant/ltp/commit/5cca17f633

Any comments are welcomed.

Thanks,
Caspar