staging: bcm2835-v4l2: Update the driver to the current VCHI API.

49bec49f ("staging: vc04_services: remove vchiq_copy_from_user")
removed the flags/msg_handle arguments, which were unused, and pushed
the implementation of copying using memcpy vs copy_from_user to the
caller.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>