nanostack unittests: do not contain license headers

[0xc0170]

Description

Files like https://github.com/ARMmbed/mbed-os/blob/master/features/nanostack/nanostack-hal-mbed-cmsis-rtos/cs_nvm/test/test_cs_nvm_unit/unittest do not contain any license identifier - please add SPDX identifier

cc @ARMmbed/mbed-os-ipcore

Issue request type

[ ] Question
[ ] Enhancement
[X] Bug

[ciarmcom]

Internal Jira reference: https://jira.arm.com/browse/MBOCUSTRIA-797

[artokin]

Fixed in #9753.

[0xc0170]

Thanks @artokin