rust: auxiliary: use core::ffi::CStr method names

Prepare for `core::ffi::CStr` taking the place of `kernel::str::CStr` by
avoid methods that only exist on the latter.

Link: Rust-for-Linux#1075
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Author: tamird

rust/kernel/auxiliary.rs

@@ -105,8 +105,8 @@ pub struct DeviceId(bindings::auxiliary_device_id);
 impl DeviceId {
     /// Create a new [`DeviceId`] from name.
     pub const fn new(modname: &'static CStr, name: &'static CStr) -> Self {
-        let name = name.as_bytes_with_nul();
-        let modname = modname.as_bytes_with_nul();
+        let name = name.to_bytes_with_nul();
+        let modname = modname.to_bytes_with_nul();
 
         // TODO: Replace with `bindings::auxiliary_device_id::default()` once stabilized for
         // `const`.