PRESUBMIT: drop check_rustfmt

We're dropping this from repohooks since cros format handles it now.

BUG=None
TEST=CQ passes

Change-Id: Ic08b7b7b7489b642787568d8ce212aca154fd52a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/5002656
Tested-by: chromeos-cop-builder@chromeos-cop.iam.gserviceaccount.com <chromeos-cop-builder@chromeos-cop.iam.gserviceaccount.com>
Reviewed-by: Li-Yu Yu <aaronyu@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Norman Bintang <normanbt@chromium.org>

PRESUBMIT.cfg

@@ -10,7 +10,6 @@ cargo_clippy_check: true
 
 # On by default, but required for options below.
 cros_license_check: true
-check_rustfmt: false
 
 [Hook Overrides Options]
 # Ignore HiFi file