rust: device: implement Bound device context

The Bound device context indicates that a device is bound to a driver.
It must be used for APIs that require the device to be bound, such as
Devres or dma::CoherentAllocation.

Implement Bound and add the corresponding Deref hierarchy, as well as the
corresponding ARef conversion for this device context.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20250413173758.12068-7-dakr@kernel.org


[ Add missing `::` prefix in macros. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>