rust: io: make IoMem and ExclusiveIoMem lifetime-parameterized

rust: io: make IoMem and ExclusiveIoMem lifetime-parameterized

Add a lifetime parameter to IoMem<'a, SIZE> and ExclusiveIoMem<'a,
SIZE>, storing a &'a Device<Bound> reference to tie the mapping to the
device's lifetime.

This mirrors the pci::Bar<'a, SIZE> design and enables drivers to hold
I/O memory mappings directly in their HRT private data, tied to the
device lifetime.

IoRequest::iomap_* methods now return the mapping directly instead of
wrapping it in Devres. Callers that need device-managed revocation can
call the new into_devres() method.

Acked-by: Uwe Kleine-König <ukleinek@kernel.org>
Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260525202921.124698-20-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>