staging: vchiq_arm: Fix camera device registration

Since the camera driver isn't probed via DT, we need to properly setup DMA.

Fixes: 37b7b308 ("staging/vc04_services: Register a platform device for the camera driver.")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>