MAINTAINERS: add drm_bridge_connector.[ch] files under bridge chips

Clearly this should be under bridge chips.

Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: Robert Foss <rfoss@kernel.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230914131951.2473844-1-jani.nikula@intel.com