rust: io: remove overloaded Io methods of Mmio

rust: io: remove overloaded Io methods of Mmio

Since `Mmio` now has the relevant implementations of `IoCapable`, the
default methods of `Io` can be used in place of the overloaded ones.
Remove them as well as the macros generating them.

Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Acked-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260206-io-v2-6-71dea20a06e6@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>