CONFIG_ARCH_BCM_281XX is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Broadcom BCM281XX SoC family

modulename: board_bcm281xx.ko

configname: CONFIG_ARCH_BCM_281XX

Linux Kernel Configuration
└─>Broadcom SoC Support
└─>Broadcom BCM281XX SoC family
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Enable support for the BCM281XX family, which includes
BCM11130, BCM11140, BCM11351, BCM28145 and BCM28155

source code: