Merge tag 'efi-2021-07-rc3' of https://source.denx.de/u-boot/custodians/u-boot-efi

Pull request for efi-2021-07-rc3

Documentation:

* add a man-page for the size command
* add man-page for extension command to index

Bug fixes:

* avoid build failure due to missing SHA512 hardware acceleration
* correct error handling in TCG2 protocol
* don't let user disable capsule authentication
* correct reading directories via UEFI API