Ws management API missing lib

[felipeLeast]

Summary of changes

New include to ws_management_api.h file to include fhss_config.h

Impact of changes

N/A

Migration actions required

N/A

Documentation

N/A

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Pull request type

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

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Test results

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

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Reviewers

@artokin @mikaleppanen

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[ciarmcom]

@felipeLeast, thank you for your changes.
@mikaleppanen @artokin @ARMmbed/mbed-os-maintainers please review.

[mikter]

@felipeLeast could you explain why this was done?

[felipeLeast]

@mikter Sure, I'm using this file to set some ws config and during compile it complains that fhss_timer_t has not been declared (on line 123)

[0xc0170]

CI started

[mbed-ci]

Test run: FAILED

Summary: 1 of 11 test jobs failed
Build number : 1
Build artifacts

Failed test jobs:

• jenkins-ci/mbed-os-ci_dynamic-memory-usage-lts

[0xc0170]

As this is trivial change to 5.15 for wisun, I'll merge this now.