New port: print/okc321

PostScript Printer Descriptions for the Oki C321dn, C331dn, and C531dn
printers for use with CUPS.

WWW: http://www.oki.de/support/printer/printer-drivers/detail.aspx?prodid=tcm:90-131700&driverid=tcm:90-138028-16

PR: 204095
Submitted by: Tobias Kortkamp <t@tobik.me>