rust_binder: clean `clippy::mem_replace_with_default` warning

Clippy reports:

error: replacing a value of type `T` with `T::default()` is better expressed using `core::mem::take`
--> drivers/android/binder/node.rs:690:32
|
690 | _unused_capacity = mem::replace(&mut inner.freeze_list, KVVec::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `core::mem::take(&mut inner.freeze_list)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#mem_replace_with_default
= note: `-D clippy::mem-replace-with-default` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::mem_replace_with_default)]`

The suggestion seems fine, thus apply it.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>