drm: Improve kerneldoc for drm_modeset_lock

 *     drm_modeset_drop_locks(&ctx);

 *     drm_modeset_acquire_fini(&ctx);

 *

 * On top of of these per-object locks using &ww_mutex there's also an overall

 * If all that is needed is a single modeset lock, then the &struct

 * drm_modeset_acquire_ctx is not needed and the locking can be simplified

 * by passing a NULL instead of ctx in the drm_modeset_lock()

 * call and, when done, by calling drm_modeset_unlock().

 *

 * On top of these per-object locks using &ww_mutex there's also an overall

 * &drm_mode_config.mutex, for protecting everything else. Mostly this means

 * probe state of connectors, and preventing hotplug add/removal of connectors.

 *

 * @lock: lock to take

 * @ctx: acquire ctx

 *

 * If ctx is not NULL, then its ww acquire context is used and the

 * If @ctx is not NULL, then its ww acquire context is used and the

 * lock will be tracked by the context and can be released by calling

 * drm_modeset_drop_locks().  If -EDEADLK is returned, this means a

 * deadlock scenario has been detected and it is an error to attempt

 * to take any more locks without first calling drm_modeset_backoff().

 *

 * If @ctx is NULL then the function call behaves like a normal,

 * non-nesting mutex_lock() call.

 */

int drm_modeset_lock(struct drm_modeset_lock *lock,

		struct drm_modeset_acquire_ctx *ctx)