New license request: NuttX-PublicDomain [SPDX-Online-Tools]

[jerpelea]

1. License Name: NuttX-PublicDomain
2. Short identifier: NuttX-PublicDomain
3. License Author or steward:
4. Comments: The public domain licenses used by NuttX RTOS have been grouped under the "NuttX-PublicDomain" license and assigned by the project a local SPDX identifier. For SBOM interoperability this identifier should be contributed to the SPDX License List.
5. License Request Url: http://tools.spdx.org/app/license_requests/426
6. URL(s): https://github.com/apache/nuttx/blob/master/include/crypto/sha1.h
7. OSI Status: 0
8. Example Projects: https://github.com/apache/nuttx

[kestewart]

@jlovejoy @swinslow - When I met with Alin, given the amount of this license in the wild in this popular RTOS, it should be a good candidate to have a license identifier assigned.