[coreboot] gitreview.sh for attaching reviewers to patches on upload

[Aaron Durbin]

It's attached. You may want to remove/tweak some of the bits. I
haven't used the cc part in quite some time. There are no options as
this was quick and dirty.

It will need an upstream tracking branch in git config to work. i.e.
git checkout -b my_work upstream/master

$ gitreview.sh  adurbin
git push --receive-pack='git receive-pack --reviewer=adurbin
--cc=<cc_someone>' upstream HEAD:refs/for/master

I then just paste the output because I don't always trust it. I find it useful.

-Aaron