drm/bridge: Fix kernel-doc typo in desc of output_bus_cfg in drm_bridge_state

There's an obvious copy-paste error in the description of
output_bus_cfg. Fix it.

Fixes: f32df58a ("drm/bridge: Add the necessary bits to support bus format negotiation")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230817094808.1.I41b04c3a8305c9f1c17af886c327941c5136ca3b@changeid