probe: Remove deprecated probe_cmdline

No platforms are probing from kernel command line.

BUG=chromium:982692
TEST=emerge-$BOARD mosys

Change-Id: Ifc1f1a70761ae370044036fcc8641df5cbc4bdcb
Reviewed-on: https://chromium-review.googlesource.com/1697963
Tested-by: Hung-Te Lin <hungte@chromium.org>
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Philip Chen <philipchen@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
2 files changed