Various EFI fixes:
- 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
- Clean up some x86 EFI stub details, some of which are borderline bugs
that copy around garbage into padding fields - let's fix these
out of caution.
- Fix build issues while working on RISC-V support
- Avoid --whole-archive when linking the stub on arm64
Signed-off-by: Ingo Molnar <mingo@kernel.org>