The kernel builds `core` with the `no_fp_fmt_parse` `--cfg`, which means
we do not have support for formatting floating point primitives. However,
`zerocopy` expects those implementations to exist:

    error[E0277]: `f32` doesn't implement `core::fmt::Display`
       --> rust/zerocopy/src/byteorder.rs:172:29
        |
    172 |                   $trait::fmt(&self.get(), f)
        |                   ----------- ^^^^^^^^^^^ the trait `core::fmt::Display` is not implemented for `f32`
        |                   |
        |                   required by a bound introduced by this call
    ...
    907 | / define_type!(
    908 | |     An,
    909 | |     "A 32-bit floating point number",
    910 | |     F32,
    ...   |
    922 | |     []
    923 | | );
        | |_- in this macro invocation
        |
        = help: the following other types implement trait `core::fmt::Display`:
                  i128
                  i16
                  i32
                  i64
                  i8
                  isize
                  u128
                  u16
                and 4 others
        = note: this error originates in the macro `impl_fmt_trait` which comes from the expansion of the macro `define_type` (in Nightly builds, run with -Z macro-backtrace for more info)

Thus work around it by skipping those implementations in `zerocopy`.

Ideally, `zerocopy` would have the equivalent of `no_fp_fmt_parse`;
and, indeed, upstream just added it [1] after I filed an issue [2]
about it as requested. We can try it in a future update of our
vendored copy.

Cc: Joshua Liebow-Feeser <joshlf@google.com>
Cc: Jack Wrenn <jswrenn@google.com>
Link: google/zerocopy#3429 [1]
Link: google/zerocopy#3426 [2]
Link: https://patch.msgid.link/20260608141439.182634-11-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>