CONFIG_SUBARCH_AVR32B is not available for thedefaultarchitecture x86.
Result is shown for architecture avr32

CONFIG_SUBARCH_AVR32B (not configurable)

modulename: entry-avr32b.ko

configname: CONFIG_SUBARCH_AVR32B

Linux Kernel Configuration
└─>System Type and features
└─>SUBARCH_AVR32B
In linux kernel since version 2.6.19 (release Date: 2006-11-29)  
source code:
arch/avr32/kernel/