staging: vt6655: Replace VNSvOutPortW with iowrite16

Replace macro VNSvOutPortW with iowrite16 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/ded437e27cffb040865d4afe47e447c2d0d6f0b8.1653203927.git.philipp.g.hortmann@gmail.com


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