MIPS: BCM47xx: Activate SSB_B43_PCI_BRIDGE by default

B43_pci_bridge is needed to use the b43 driver with brcm47xx.  Activate it
by default if PCI is available.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1510/


Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>