build_sdk_board: merge sudo multi stages

Might as well run these altogether and save a few seconds.

BUG=b:193915549
TEST=SDK builder passes

Change-Id: Ifc947e0badb65ab5c86ae6b2ec68e710ce3582db
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3248587
Reviewed-by: Sloan Johnson <sloanjohnson@google.com>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed