struct vchiq_mmal_rect is only referenced from mmal-parameters.h, yet
was defined in mmal-vchiq.h.

Move it to avoid having to include multiple headers for no reason.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>