efi_loader: remove EFI_HII_CONFIG_ROUTING_PROTOCOL

Our implementation of the EFI_HII_CONFIG_ROUTING_PROTOCOL is a mere stub,
where all services return an error code. The protocol is neither needed for
the EFI shell nor for the UEFI SCT. To reduce the code size remove it from
the U-Boot binary.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>