staging: vchiq: Use the old dma controller for OF config on platform devices

vchiq on Pi4 is no longer under the soc node, therefore it
doesn't get the dma-ranges for the VPU.

Switch to using the configuration of the old dma controller as
that will set the dma-ranges correctly.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>