serial: 8250_pci: Fix number of ports for ACCES serial cards

Have the correct number of ports created for ACCES serial cards. Two port
cards show up as four ports, and four port cards show up as eight.

Fixes: c8d19242 ("serial: 8250: added acces i/o products quad and octal serial cards")
Signed-off-by: Jay Dolan <jay.dolan@accesio.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>