CONFIG_ARCH_BCM_MOBILE_L2_CACHE is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Broadcom mobile SoC level 2 cache support

modulename: kona_l2_cache.ko

configname: CONFIG_ARCH_BCM_MOBILE_L2_CACHE

Linux Kernel Configuration
└─>Broadcom SoC Support
└─>Broadcom mobile SoC level 2 cache support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
source code:
arch/arm/mach-bcm/kona_l2_cache.c