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

CONFIG_ARCH_BCM_IPROC (not configurable)

configname: CONFIG_ARCH_BCM_IPROC

Linux Kernel Configuration
└─>Broadcom SoC Support
└─>ARCH_BCM_IPROC
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This enables support for systems based on Broadcom IPROC architected SoCs.
The IPROC complex contains one or more ARM CPUs along with common
core periperals. Application specific SoCs are created by adding a
uArchitecture containing peripherals outside of the IPROC complex.
Currently supported SoCs are Cygnus.