rust: io: cleanup imports and use "kernel vertical" style

Commit 46f045db5a ("rust: Add read_poll_timeout_atomic function")
initiated the first import change in the I/O module using the agreed
"kernel vertical" import style [1].

For consistency throughout the module, adjust all other imports
accordingly.

While at it, drop unnecessary imports covered by prelude::*.

Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
Reviewed-by: Zhi Wang <zhiw@nvidia.com>
Link: https://patch.msgid.link/20251104133301.59402-1-dakr@kernel.org
[ Use prelude::* in io/poll.rs. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

rust/kernel/io.rs

@@ -4,8 +4,10 @@
 //!
 //! C header: [`include/asm-generic/io.h`](srctree/include/asm-generic/io.h)
 
-use crate::error::{code::EINVAL, Result};
-use crate::{bindings, build_assert, ffi::c_void};
+use crate::{
+    bindings,
+    prelude::*, //
+};
 
 pub mod mem;
 pub mod poll;

rust/kernel/io/mem.rs

@@ -4,16 +4,24 @@
 
 use core::ops::Deref;
 
-use crate::c_str;
-use crate::device::Bound;
-use crate::device::Device;
-use crate::devres::Devres;
-use crate::io;
-use crate::io::resource::Region;
-use crate::io::resource::Resource;
-use crate::io::Io;
-use crate::io::IoRaw;
-use crate::prelude::*;
+use crate::{
+    c_str,
+    device::{
+        Bound,
+        Device, //
+    },
+    devres::Devres,
+    io::{
+        self,
+        resource::{
+            Region,
+            Resource, //
+        },
+        Io,
+        IoRaw, //
+    },
+    prelude::*,
+};
 
 /// An IO request for a specific device and resource.
 pub struct IoRequest<'a> {

rust/kernel/io/poll.rs

@@ -5,7 +5,7 @@
 //! C header: [`include/linux/iopoll.h`](srctree/include/linux/iopoll.h).
 
 use crate::{
-    error::{code::*, Result},
+    prelude::*,
     processor::cpu_relax,
     task::might_sleep,
     time::{

rust/kernel/io/resource.rs

@@ -5,12 +5,16 @@
 //!
 //! C header: [`include/linux/ioport.h`](srctree/include/linux/ioport.h)
 
-use core::ops::Deref;
-use core::ptr::NonNull;
+use core::{
+    ops::Deref,
+    ptr::NonNull, //
+};
 
-use crate::prelude::*;
-use crate::str::{CStr, CString};
-use crate::types::Opaque;
+use crate::{
+    prelude::*,
+    str::CString,
+    types::Opaque, //
+};
 
 /// Resource Size type.
 ///