CMake targets: remove labels usage, not required anymore

[0xc0170]

Summary of changes

As targets refactor was completed, this can be removed. I could not find any usage of targets labels in targets folder, this was the last one.

Impact of changes

Migration actions required

Documentation

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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

[] 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

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Reviewers

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[ciarmcom]

@0xc0170, thank you for your changes.
@ARMmbed/mbed-os-maintainers please review.

[0xc0170]

CI started

[mbed-ci]

Jenkins CI Test : ❌ FAILED

Build Number: 1 | 🔒 Jenkins CI Job | 🌐 Logs & Artifacts

CLICK for Detailed Summary

jobs	Status
jenkins-ci/mbed-os-ci_unittests	✔️
jenkins-ci/mbed-os-ci_build-greentea-ARM	✔️
jenkins-ci/mbed-os-ci_build-greentea-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_cmake-example-GCC_ARM	❌
jenkins-ci/mbed-os-ci_build-example-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_build-example-ARM	✔️
jenkins-ci/mbed-os-ci_build-cloud-example-ARM	✔️
jenkins-ci/mbed-os-ci_cmake-example-ARM	❌
jenkins-ci/mbed-os-ci_build-cloud-example-GCC_ARM	✔️

[0xc0170]

One duplication found

CMake Error at mbed-os/targets/TARGET_NXP/TARGET_MCUXpresso_MCUS/CMakeLists.txt:11 (add_library):
add_library cannot create target "mbed-mcuxpresso-mcus" because another
target with the same name already exists. The existing target is an
interface library created in source directory
"/builds/workspace/mbed-os-ci_cmake-example-ARM@8/examples/mbed-os-example-blinky/mbed-os/targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS".
See documentation for policy CMP0002 for more details.

I'll fix this one now

[0xc0170]

Fixed, restarting CI

[mbed-ci]

Jenkins CI Test : ✔️ SUCCESS

Build Number: 2 | 🔒 Jenkins CI Job | 🌐 Logs & Artifacts

CLICK for Detailed Summary

jobs	Status
jenkins-ci/mbed-os-ci_unittests	✔️
jenkins-ci/mbed-os-ci_cmake-example-ARM	✔️
jenkins-ci/mbed-os-ci_cmake-example-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_build-greentea-ARM	✔️
jenkins-ci/mbed-os-ci_build-greentea-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_build-example-ARM	✔️
jenkins-ci/mbed-os-ci_build-example-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_build-cloud-example-ARM	✔️
jenkins-ci/mbed-os-ci_build-cloud-example-GCC_ARM	✔️
jenkins-ci/mbed-os-ci_greentea-test	✔️
jenkins-ci/mbed-os-ci_cmake-example-test	✔️