MAINTAINERS: add Rust device abstractions to DRIVER CORE

Add missing file path of the Rust abstractions to the maintainers entry,
until we can move it to 'drivers/base/'.

Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://lore.kernel.org/r/20240619133949.64638-2-dakr@redhat.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>