Merge tag 'efi-2022-04-rc2-2' of https://source.denx.de/u-boot/custodians/u-boot-efi

Pull request for efi-2022-04-rc2-2

UEFI

* add unit test for RISCV_EFI_BOOT_PROTOCOL
* disable UEFI for Colibri VF610
* add handle for UART
* fix printing of Unicode strings
* simplify enumeration of block devices