CONFIG_ARCH_BCM2835 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Broadcom BCM2835 family

modulename: board_bcm2835.ko

and/or

irq-bcm2835.ko

and/or

irq-bcm2836.ko

and/or

clk-bcm2835.ko

and/or

clk-bcm2835-aux.ko

configname: CONFIG_ARCH_BCM2835

Linux Kernel Configuration
└─>Broadcom SoC Support
└─>Broadcom BCM2835 family
In linux kernel since version 3.1 (release Date: 2011-10-24)  
This enables support for the Broadcom BCM2835 and BCM2836 SoCs.
This SoC is used in the Raspberry Pi and Roku 2 devices.

source code:
arch/arm/mach-bcm/board_bcm2835.c


is selected by
CONFIG_MMC_SDHCI_IPROC