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

Broadcom mobile SoC SMP support

modulename: kona_smp.ko

and/or

platsmp.ko

configname: CONFIG_ARCH_BCM_MOBILE_SMP

Linux Kernel Configuration
└─>Broadcom SoC Support
└─>Broadcom Mobile SoC Selection
└─>Broadcom mobile SoC SMP support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
SMP support for the BCM281XX and BCM21664 SoC families.
Provided as an option so SMP support for SoCs of this type
can be disabled for an SMP-enabled kernel.

source code:
arch/arm/mach-bcm/kona_smp.c


is depended by
CONFIG_ARCH_BCM_MOBILE