DeviceKey Root of Trust not generated

[LDong-Arm]

Description of defect

When running this example on a board with TRNG, and if the board's flash doesn't contain a Root of Trust already, the example fails:

--- Error, derive key failed with error code -5 ---

This is because the generation of Root of Trust is missing. Since ARMmbed/mbed-os#12385 was merged, the Root of Trust is not automatically generated anymore.

Target(s) affected by this defect ?

Any target with TRNG (e.g. DISCO_L475VG_IOT01A)

Toolchain(s) (name and version) displaying this defect ?

Any

What version of Mbed-os are you using (tag or sha) ?

mbed-os-6.9.0

What version(s) of tools are you using. List all that apply (E.g. mbed-cli)

Any

How is this defect reproduced ?

Erase any existing DeviceKey Root of Trust (if any), then build and run this example on a DISCO_L475VG_IOT01A board (for example).

[ciarmcom]

Thank you for raising this detailed GitHub issue. I am now notifying our internal issue triagers.
Internal Jira reference: https://jira.arm.com/browse/IOTOSM-3821

[LDong-Arm]

Fixes:

• Example: Generate DeviceKey Root of Trust, update Mbed CLI 2 support #72
• Documentation update: Fix DeviceKey documentation regarding RoT mbed-os#14550

[Patater]

Fixed by #72