Updates the ICM peripheral to use the `clock::v2` API

[kyp44]

Summary

As part of the clock::v2 effort tracked in Issue #912, this PR updates the icm to use the clock::v2 API by requiring ownership of its AhbClk and ApbClk. Note that this peripheral is only on thumbv7 targets.

No examples on any Tier 1 BSPs use the ICM so none were affected.

Checklist

• [X] All new or modified code is well documented, especially public items
• [X] No new warnings or clippy suggestions have been introduced - CI will deny clippy warnings by default! You may #[allow] certain lints where reasonable, but ideally justify those with a short comment.

[rnd-ash]

Looks good to me! Appreciate the documentation updates as well.

[kyp44]

@ianrrees Removed the underscores in the latest commit, and also did so in PR #925 for the same reason.