[SERIAL] Fix two bugs in parport_serial

Steinar H. Gunderson reported:

  - For some reason, it detects the 9845 as a 9735 -- it appears this is
    simply related to the ordering in parport_serial_pci_tbl[]. If we move
    the 9845 up above the 9735, it prints out 9710:9845, but no change in
    behaviour. (We didn't find out why this was the case; we left it alone
    since it didn't affect our problem.)
  - The card has no parallel port (at least no physical ones), yet it reports
    (via its subsystem ID of 0x0014) one parallel port and four serial ports.
    The probe for the parallel port fails, and the driver just aborts. Thus,
    it doesn't find the serial ports.

Fix the debugging code to use dev_dbg, but don't bother displaying the
PCI ID of the detected board (that's accessible via other means.)

Also, arrange for parport_register() to return 0 even if it finds no
ports.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>