cbuildbot_config: disable ChromeSDK stage on sonic
cbuildbot_config: disable ChromeSDK stage on sonic

Since chrome_sync is also false for this configuration, disable
the chrome_sdk stage as well.

Until we sort out the issues with Chrome SDK generation, disable it.

BUG=chromium:297694
TEST=trybot on sonic-release only shows failure in ArchiveStage now.

Change-Id: Ibf0424411d8fa15e6fc5fc6eb94ce42b9fc6160e
Reviewed-on: https://chromium-review.googlesource.com/185669
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
Commit-Queue: Gaurav Shah <2987db6a10bcfe664554a372d01e80df7fd325a3@chromium.org>
Tested-by: Gaurav Shah <2987db6a10bcfe664554a372d01e80df7fd325a3@chromium.org>
Reviewed-by: Albert Chaulk <463ebca44c4fd818f835a193c6e38dafda91ae9f@chromium.org>

bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite