CONFIG_ARCH_BCM_IPROC is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64

Broadcom iProc SoC Family

configname: CONFIG_ARCH_BCM_IPROC

Linux Kernel Configuration
└─>Platform selection
└─>Broadcom iProc SoC Family
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This enables support for Broadcom iProc based SoCs