Add BSD-Patent to the list of OK, but approval required licenses.

The EDK2 project has migrated to the BSD-Patent license from
https://opensource.org/licenses/BSDplusPatent for much of their code
base. Get pre-approval for future imports from EDK2 and be explicit
about needing core approval for new components.

Reviewed by: allanjude@, bcr@, brooks@, seanc@
Approved by: core@
Differential Revision: https://reviews.freebsd.org/D20761