rust: kernel: add `LocalModule` fallback for `#[vtable]` `impl`s

Like commit 98f256e27262 ("rust: doctest: add LocalModule fallback
for #[vtable] ThisModule"), add another `LocalModule` struct with a
null-pointer `ModuleMetadata` `impl` for the `kernel` crate, so that
`crate::LocalModule` (auto-inserted by `#[vtable]`) resolves correctly
when there is no `module!` macro.

This will be needed by DRM to use `#[vtable]` `impl` blocks in KUnit
tests within the `kernel` crate [1].

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/rust-for-linux/DKNAS52KYWLD.M15VEC6U0F6R@kernel.org/ [1]
[ Created commit out of the diff in the link above. Fixed the
  `clippy::undocumented_unsafe_blocks` lint by wrapping with a block
  like in the other commit too. Added `#[allow(dead_code)]` until we
  actually (and unconditionally, i.e. KUnit tests may be not enabled)
  use it. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

0 files changed, 0 insertions, 0 deletions