Merge tag 'efi-2020-07-rc6-2' of https://gitlab.denx.de/u-boot/custodians/u-boot-efi

Pull request for UEFI sub-system for efi-2020-07-rc6 (2)

Fix an incorrect update of the GD register in efi_get_variable_common().
Fix an incorrect check for an FDT reg property.
Fix a device tree used for Python testing.