Remove cros.rf modules dedicated for factory tests.

The RF tests have been all merged to src/platform/factory and no one is still
using RF modules in autotest folder.

BUG=chromium:394254
TEST=Search autotest source tree and not seeing "cros.rf".

Change-Id: Ied3509af75aab5d875aa3f8f8b62862aba0bba1c
Reviewed-on: https://chromium-review.googlesource.com/209282
Reviewed-by: Mao Huang <littlecvr@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
9 files changed