gpu: host1x: Correct trivial kernel-doc inconsistencies

Silence documentation build warnings by adding kernel-doc fields.

./include/linux/host1x.h:69: warning: Function parameter or member 'parent' not described in 'host1x_client'
./include/linux/host1x.h:69: warning: Function parameter or member 'usecount' not described in 'host1x_client'
./include/linux/host1x.h:69: warning: Function parameter or member 'lock' not described in 'host1x_client'
Signed-off-by: NColton Lewis <colton.w.lewis@protonmail.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>

include/linux/host1x.h

@@ -48,6 +48,9 @@ struct host1x_client_ops {
  * @channel: host1x channel associated with this client
  * @syncpts: array of syncpoints requested for this client
  * @num_syncpts: number of syncpoints requested for this client
+ * @parent: pointer to parent structure
+ * @usecount: reference count for this structure
+ * @lock: mutex for mutually exclusive concurrency
  */
 struct host1x_client {
 	struct list_head list;