Merge tag 'efi-2020-10-rc3' of https://gitlab.denx.de/u-boot/custodians/u-boot-efi

Pull request for UEFI sub-system for efi-2020-10-rc3

Bugs in the UEFI sub-system are fixed:

* use the optional data of the BootXXXX variables as load options
* simplify function public_key_verify_signature()
* amend a copyright notice