Pull EFI fixes from Ard Biesheuvel:
- Fix the layering violation in the use of the EFI runtime services
availability mask in users of the 'efivars' abstraction
- Revert build fix for GCC v4.8 which is no longer supported
- Some fixes for build issues found by Atish while working on RISC-V support
- Avoid --whole-archive when linking the stub on arm64
- Some x86 EFI stub cleanups from Arvind