nyan_big: Fix typo of compatible string in board strappings.

This fix typo for revisions 3-5.

BUG=chrome-os-partner:28705
TEST=Built for big, booted on big.
BRANCH=None

Change-Id: Idc18e417c915181868f1f329895c5a0d912fdd1e
Signed-off-by: Artiste Hsu <chhsu@nvidia.com>
Reviewed-on: https://chromium-review.googlesource.com/198979
Reviewed-by: Gabe Black <gabeblack@chromium.org>
1 file changed