Rust Dependency: Update r-efi requirement from 5 to 6

[dependabot]

Updates the requirements on r-efi to permit the latest version.

Release notes

Sourced from r-efi's releases.

r-efi-6.0.0

# r-efi - UEFI Reference Specification Protocol Constants and Definitions
CHANGES WITH 6.0.0:
* Change all function prototypes to use `unsafe fn`. This is a major
  change, but reflects what all downstream users have already assumed.


Drop the obsolete efiapi and examples feature flags. The former

was unused, and the latter is an alias for native.


The eficall!{} macro is now fully inline in all of r-efi. It is

still provided for external users, but will no longer be used by

r-efi. All users are recommended to use extern "efiapi" directly.


Contributions from: Alan Egerton, David Rheinsberg

Dußlingen, 2026-02-03

Changelog

Sourced from r-efi's changelog.

CHANGES WITH 6.0.0:

    * Change all function prototypes to use `unsafe fn`. This is a major
      change, but reflects what all downstream users have already assumed.
* Drop the obsolete `efiapi` and `examples` feature flags. The former
  was unused, and the latter is an alias for `native`.

The eficall!{} macro is now fully inline in all of r-efi. It is

still provided for external users, but will no longer be used by

r-efi. All users are recommended to use extern "efiapi" directly.

Contributions from: Alan Egerton, David Rheinsberg

Dußlingen, 2026-02-03

CHANGES WITH 5.3.0:

    * Remove the optional dependency on `compiler-builtins`, which was
      needed to build r-efi as part of rustc. This is no longer necessary.
Contributions from: David Rheinsberg, Trevor Gross

Dußlingen, 2025-06-17

CHANGES WITH 5.2.0:

    * Add the memory attribute protocol.
Contributions from: David Rheinsberg, Oliver Smith-Denny

Dußlingen, 2024-12-22

CHANGES WITH 5.1.0:

    * Mark `Guid::as_bytes` and `Guid::from_bytes` as `const fn`, aligning
      them with the other methods on `Guid`. This helps creating constant
      GUIDs via macros or other external helpers.
Contributions from: Christopher Zurcher, David Rheinsberg

Dußlingen, 2024-09-01

CHANGES WITH 5.0.0:

    * Change the type of the `unload` function-pointer of the Loaded Image
      Protocol to `Option<Unload>`, given that it can be `NULL` to indicate
      that the image cannot be unloaded.
      This is a major API break, but any users very likely need to adjust
      anyway to avoid NULL-derefs.

... (truncated)

Commits

• 7e1b032 r-efi: prepare v6.0.0
• 96504bb r-efi: inline eficall!{}
• ea21433 build: drop unused feature flags
• 48b1a11 r-efi: extend the transpose guidelines
• e701536 build: synchronize AUTHORS
• 6f2330e r-efi: update remaining prototypes to unsafe fn
• 60793e0 Fix signatures of most EFI functions to be unsafe
• 97b55be build: prepare v5.3.0
• addacc1 Remove compiler-builtins from rustc-dep-of-std dependencies
• 345756a ci: use shared publish-workflow
• Additional commits viewable in compare view

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