bcma: Add BCM43225 PCI id to bcma-pci-bridge

Adds 0xa8d8 PCI to BCMA-PCI bridge device id table, enabling brcmsmac
driver support for this PCI/chip id configuration (BCM43225 on Sagemcom
F@ST2704v2 ADSL router).

Original discussion: http://eko.one.pl/forum/viewtopic.php?id=4666&p=4