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()