USB: pl2303: add AdLink ND-6530 USB IDs

I read a rumor that the AdLink ND6530 USB RS232, RS422 and RS485
isolated adapter is actually a PL2303 based usb serial adapter. I
tried it out, and as far as I can tell it works.

Signed-off-by: Manuel Jander <manuel.jander@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>