rust: miscdevice: remove redundant imports

Drop `Error`, `Result`, `Pin`, `c_int`, `c_long`, `c_uint`, and
`c_ulong` imports already provided by `kernel::prelude`.

Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
Reviewed-by: Onur Özkan <work@onurozkan.dev>
Link: https://patch.msgid.link/20260520-miscdev-use-format-v2-3-64dc48fc1345@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rust/kernel/miscdevice.rs

@@ -13,16 +13,8 @@
     device::Device,
     error::{
         to_result,
-        Error,
-        Result,
         VTABLE_DEFAULT_ERROR, //
     },
-    ffi::{
-        c_int,
-        c_long,
-        c_uint,
-        c_ulong, //
-    },
     fs::{
         File,
         Kiocb, //
@@ -39,10 +31,7 @@
         Opaque, //
     },
 };
-use core::{
-    marker::PhantomData,
-    pin::Pin, //
-};
+use core::marker::PhantomData;
 
 /// Options for creating a misc device.
 #[derive(Copy, Clone)]