mario: Remove "variant" subcommand

This doesn't seem to do anything useful since the value read from
the EC only ever translates to "Unknown."

BUG=none
BRANCH=none
TEST=it builds

Change-Id: I440d8be925e92220b91601f9956460e2db0c0693
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/427340
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Martin Roth <martinroth@chromium.org>
2 files changed