rust: i2c: Update ARef and AlwaysRefCounted imports to use sync::aref

rust: i2c: Update ARef and AlwaysRefCounted imports to use sync::aref

Update call sites in `i2c.rs` to import `ARef` and
`AlwaysRefCounted` from `sync::aref` instead of `types`.

This aligns with the ongoing effort to move `ARef` and
`AlwaysRefCounted` to sync.

Suggested-by: Benno Lossin <lossin@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1173
Signed-off-by: Shankari Anand <shankari.ak0208@gmail.com>
Acked-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://patch.msgid.link/20260102202714.184223-3-shankari.ak0208@gmail.com
[ Move `ARef` import into the `kernel` `use` tree above. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>