drm/bridge: panel: Add a device link between drm device and panel device

Add the device link when panel bridge is attached and delete the link
when panel bridge is detached.  The drm device is the consumer while
the panel device is the supplier.  This makes sure that the drm device
suspends eariler and resumes later than the panel device, hence resolves
problems where the order is reversed, like the problematic case mentioned
in the below link.

Link: https://lore.kernel.org/lkml/CAPDyKFr0XjrU_udKoUKQ_q8RWaUkyqL+8fV-7s1CTMqi7u3-Rg@mail.gmail.com/T/
Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230807061115.3244501-1-victor.liu@nxp.com