Merge tag 'efi-2020-10-rc3-3' of https://gitlab.denx.de/u-boot/custodians/u-boot-efi

Pull request for UEFI sub-system for efi-2020-10-rc3 (3)

The following bug fixes are contained in this pull-request:

* ResetSystem() should no hang if not implemented.
* Device paths in Bootxxxx variables should be verified.
* Use ':' as separator for command setenv -e -i instead of ','.
* Correct comments for functions.
* Update UEFI documentation.