build(droplet): add DEVICEIMPL as imported library

[lljbash]

Motivation and Context

最近的更新中给 DEVICEIMPL target 增加了属性，但是 s2 的 build 之前写得很不好，没有这个 target，导致无法 config。

Description

加入一个 imported target。

Use cases (Optional)

BC-breaking (Optional)

Checklist

Before PR:

• I have read and followed the workflow indicated in the Contributors.md to create this PR.
• Pre-commit or linting tools indicated in Contributors.md are used to fix the potential lint issues.
• Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• New functionalities are covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• CLA has been signed and all committers have signed the CLA in this PR.