make use of `Zeroable` improvements

[BennoLossin]

The "Zeroable improvements & bindings integration" patch series introduced the ability to call pin_init::zeroed() for values implementing the Zeroable trait instead of having to call the unsafe fn zeroed from core::mem. From that series, only patches 1, 2 and 11 have been merged, since the others should go through the respective maintainers. I don't have enough time to see all patches through, so as a good first issue, you can re-send my patch to the list (please read the patch submission process on how to do this).

Here are the current patches & their files that still need sending:

• rust/kernel/miscdevice.rs
• rust/kernel/net/phy.rs
• rust/kernel/block/mq/gen_disk.rs and rust/kernel/block/mq/tag_set.rs
• rust/kernel/of.rs
• rust/kernel/drm/gem/mod.rs
• rust/kernel/security.rs
• rust/kernel/auxiliary.rs
• rust/kernel/acpi.rs

If you see another usage that could make use of this pattern, feel free to send an unrelated patch!

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This requires submitting a proper patch to the LKML and the Rust for Linux mailing list. Please recall to test your changes (including generating the documentation if changed, running the Rust doctests if changed, etc.), to use a proper title for the commit, to sign your commit under the Developer's Certificate of Origin and to add a Suggested-by: tag, and a Link: tag to this issue. Please see https://docs.kernel.org/process/submitting-patches.html and https://rust-for-linux.com/contributing for details.