ANDROID: fix build breakages with Rust alloc backport

When backporting the Rust alloc and FFI integer changes, there is some
breakage in ashmem and related files due to API changes. Thus, update
these files to use the new API.

This should be applied at the same time as the merge of the stable
release containing this backport.

Link: https://lore.kernel.org/all/20250307225008.779961-1-ojeda@kernel.org/


Change-Id: I31aeaca89eb007302d1738e1be9d3789e92b404c
Fixes: 1ef4cf5f ("rust: alloc: update module comment of alloc.rs")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
[Removed FFI integer changes because the stable backport does not yet
 contain those. <mmaurer@google.com>]
Signed-off-by: Matthew Maurer <mmaurer@google.com>