CONFIG_CPU_SH3 is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

CONFIG_CPU_SH3 (not configurable)

configname: CONFIG_CPU_SH3

Linux Kernel Configuration
└─>System type
└─>CPU_SH3
In linux kernel since version 2.6.12  

is selected by
CONFIG_SND_SH_DAC_AUDIO