samples: rust: remove imports available via prelude

These imports are already in scope by importing `kernel::prelude::*` and
does not need to be imported separately.

Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260123172007.136873-4-gary@garyguo.net
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

samples/rust/rust_driver_auxiliary.rs

@@ -16,7 +16,6 @@ use kernel::{
 };
 
 use core::any::TypeId;
-use pin_init::PinInit;
 
 const MODULE_NAME: &CStr = <LocalModule as kernel::ModuleMetadata>::NAME;
 const AUXILIARY_NAME: &CStr = c_str!("auxiliary");

samples/rust/rust_misc_device.rs

@@ -95,8 +95,6 @@
 //! }
 //! ```
 
-use core::pin::Pin;
-
 use kernel::{
     c_str,
     device::Device,

samples/rust/rust_print_main.rs

@@ -101,7 +101,7 @@ impl Drop for RustPrint {
 }
 
 mod trace {
-    use kernel::ffi::c_int;
+    use kernel::prelude::*;
 
     kernel::declare_trace! {
         /// # Safety