sandbox: Add an explanation of the sandbox variants
authorSimon Glass <sjg@chromium.org>
Wed, 19 Sep 2018 00:43:28 +0000 (18:43 -0600)
committerSimon Glass <sjg@chromium.org>
Sat, 29 Sep 2018 17:49:35 +0000 (11:49 -0600)
commit969c8f4d5a341ee5ba47dbbe8cf382a250eb8cb7
tree9ebcb8b60fc78f9843882ea07d554890f35ef0cc
parente62a24ce27ab86efc1b37d14112c29d3f2010238
sandbox: Add an explanation of the sandbox variants

There are quite a few builds of sandbox now. Add information about these
to the README.

Signed-off-by: Simon Glass <sjg@chromium.org>
board/sandbox/README.sandbox