staging: vt6655: Replace VNSvOutPortD with iowrite32

Replace macro VNSvOutPortD with iowrite32 because it replaces
just one line.
The name of macro and the arguments use CamelCase which
is not accepted by checkpatch.pl

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/03b6ff0250aa797f45a855ff2fc76f8013f73dc0.1653203927.git.philipp.g.hortmann@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>