build_packages.sh: disallow rebuilding hps-sdk from source

Like dev-lang/rust, hps-sdk is expensive to build and requires all cross
compilers so we want it to always be installed as a binpkg from the SDK
builder.

BUG=b:219958360
TEST=./build_packages.sh --board=brya

Change-Id: I6daa21072c2e92661df2f45f7777533d2ce38b31
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3470214
Tested-by: Dan Callaghan <dcallagh@chromium.org>
Reviewed-by: Sergey Frolov <sfrolov@google.com>
Commit-Queue: Dan Callaghan <dcallagh@chromium.org>
1 file changed