cros_ec.c: Fix switch fallthrough to be explicit

Work towards building with upstreams CFLAGS.

BUG=b:151281822
BRANCH=none
TEST=builds

Change-Id: I2fa46c6cf8390bf62b28978fbfe4f166ed1e1f43
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/flashrom/+/2137159
Tested-by: Edward O'Callaghan <quasisec@chromium.org>
Auto-Submit: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Commit-Queue: Edward O'Callaghan <quasisec@chromium.org>
1 file changed