EFI backports from v6.11-rc to v6.6 and newer

[Ard Biesheuvel <ardb@xxxxxxxxxx>]

Please consider the following patches (in this order) for backporting
to v6.6 and newer.

fb318ca0a522295edd6d796fb987e99ec41f0ee5
ae835a96d72cd025421910edb0e8faf706998727

The second patch addresses a regression on older Dell hardware. The
first one is a prerequisite for the second one, and a minor bugfix
itself.

Thanks,
Ard.