DTLSSocketWrapper: Convert to Chrono

[kjbracey]

Summary of changes

Convert DTLS wrapper to use new APIs from #12425.

Impact of changes

Eliminate use of deprecated APIs

Migration actions required

n/a

Documentation

None

---

Pull request type

[] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[X] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

---

Test results

[] No Tests required for this change (E.g docs only update)
[X] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

---

Reviewers

---

[ciarmcom]

@kjbracey-arm, thank you for your changes.
@ARMmbed/mbed-os-ipcore @ARMmbed/mbed-os-maintainers please review.

[mergify]

This PR cannot be merged due to conflicts. Please rebase to resolve them.

[kjbracey]

Rebased.

[0xc0170]

CI restarted

[mbed-ci]

Test run: FAILED

Summary: 1 of 3 test jobs failed
Build number : 1
Build artifacts

Failed test jobs:

• jenkins-ci/mbed-os-ci_unittests

[0xc0170]

unittest failed, please review

[kjbracey]

CI started

[mbed-ci]

Test run: FAILED

Summary: 1 of 3 test jobs failed
Build number : 2
Build artifacts

Failed test jobs:

• jenkins-ci/mbed-os-ci_unittests

[kjbracey]

CI started

[mbed-ci]

Test run: SUCCESS

Summary: 6 of 6 test jobs passed
Build number : 3
Build artifacts