rust: add `build_error!` to the prelude

The sibling `build_assert!` is already in the prelude, it makes sense
that a "core"/"language" facility like this is part of the prelude and
users should not be defining their own one (thus there should be no risk
of future name collisions and we would want to be aware of them anyway).

Thus add `build_error!` into the prelude.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20241123222849.350287-3-ojeda@kernel.org


[ Applied the change to the new miscdevice cases. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>