CONFIG_BCM47XX is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

Broadcom BCM47XX based boards

modulename: pci-bcm47xx.ko

configname: CONFIG_BCM47XX

System type
└─>Broadcom BCM47XX based boards
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
Support for BCM47XX based boards

source code:
arch/mips/pci/pci-bcm47xx.c

is selected by
CONFIG_BGMAC