Pull EFI updates for v4.20 from Ard Biesheuvel:
- Add support for enlisting the help of the EFI firmware to create memory
reservations that persist across kexec.
- Add page fault handling to the runtime services support code on x86 so
we can gracefully recover from buggy EFI firmware.
- Fix command line handling on x86 for the boot path that omits the stub's
PE/COFF entry point.
- Other assorted fixes.