Merge tag 'efi-next-20230325' of https://source.denx.de/u-boot/custodians/u-boot...

Pull request for efi-next-20230325

Documenation:

* add man-page for efi command

UEFI:

* Let EFI app call ExitBootServices() before legacy booting kernel
* Support zboot and bootm in the EFI app
* Let efi command show configuration tables
* Support booting a 64-bit kernel from 64-bit EFI app
* Allocate device-tree copy from high memory
* simplify efi_str_to_u16()