drm/atomic-helper: fix kerneldoc

Just a tiny copypasta mistake.

Fixes: 75146591 ("drm/bridge: Add a drm_bridge_state object")
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200214081340.2772853-1-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_atomic_state_helper.c

@@ -635,7 +635,6 @@ EXPORT_SYMBOL(__drm_atomic_helper_bridge_reset);
  * drm_atomic_helper_bridge_reset() - Allocate and initialize a bridge state
  *				      to its default
  * @bridge: the bridge this state refers to
- * @state: bridge state to initialize
  *
  * Allocates the bridge state and initializes it to default values. This helper
  * is meant to be used as a bridge &drm_bridge_funcs.atomic_reset hook for