squash! rust: drm/kms: Add bindings for drm_connector

* Improve safety comments in Connector::new()
* Switch to requiring a UnregisteredKmsDevice instead of a Device
  This is in preparation for the static/dynamic connector split, which we
  may as well prepare for since we don't have any use for dynamic
  connectors yet.

rust/kernel/drm/kms/connector.rs

@@ -7,6 +7,7 @@ use crate::{
     sync::ArcBorrow,
     drm::{
         drv::{Driver, FEAT_MODESET},
+        kms::UnregisteredKmsDevice,
         device::Device,
     },
     types::{AlwaysRefCounted, Opaque, ARef},
@@ -197,12 +198,9 @@ impl<T: DriverConnector> Connector<T> {
     ///
     /// A driver may use this to create new [`Connector`] objects.
     ///
-    /// TODO: Add a way to handle creating connectors after device registration. Also, that's why we
-    /// don't ask for a UnregisteredKms device here.
-    ///
     /// [`KmsDriver::create_objects`]: kernel::drm::kms::KmsDriver::create_objects
     pub fn new(
-        dev: &Device<T::Driver>,
+        dev: &UnregisteredKmsDevice<T::Driver>,
         type_: u32,
         args: T::Args,
     ) -> Result<ARef<Self>> {
@@ -218,7 +216,9 @@ impl<T: DriverConnector> Connector<T> {
             GFP_KERNEL
         )?;
 
-        // SAFETY: FFI call with no special safety requirements
+        // SAFETY:
+        // - We just allocated `new` above
+        // - `new` starts with `drm_connector` via its type invariants.
         to_result(unsafe {
             bindings::drm_connector_init(
                 dev.as_raw(),