drm/bridge: select DRM_KMS_HELPER for AUX_BRIDGE

drm/bridge: select DRM_KMS_HELPER for AUX_BRIDGE

The aux bridge uses devm_drm_of_get_bridge() from the panel bridge (and
correctly selects DRM_PANEL_BRIDGE). However panel bridge is not a
separate module, it is compiled into the drm_kms_helper.o. Select
DRM_KMS_HELPER too to express this dependency.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250411-aux-select-kms-v1-1-c4276f905a56@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>