drm/msm/dsi: use correct lifetime device for devm_drm_bridge_add

The lifetime of the created drm_bridge is attached to the drm_device
rather than the DSI's platform_device. Use correct lifetime for
devm_drm_bridge_add() call.

Fixes: 5f403fd7 ("drm/msm/dsi: switch to devm_drm_bridge_add()")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/562200/
Link: https://lore.kernel.org/r/20231011214705.375738-2-dmitry.baryshkov@linaro.org