Merge tag 'efi-2020-01-rc2-2' of https://gitlab.denx.de/u-boot/custodians/u-boot-efi

Pull request for UEFI sub-system for efi-2021-01-rc2 (2)

The series contains the following enhancements

* preparatory patches for UEFI capsule updates
* initialization of the emulated RTC using an environment variable

and a bug fix

* If DisconnectController() is called for a child controller that is the
  only child of the driver, the driver must be disconnected.