CONFIG_CPU_SUBTYPE_SH7751R is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

Support SH7751R processor

modulename: pci-sh7751.ko

and/or

setup-sh7750.ko

configname: CONFIG_CPU_SUBTYPE_SH7751R

Linux Kernel Configuration
└─>Processor selection
└─>Support SH7751R processor
In linux kernel since version 2.6.16 (release Date: 2006-03-19)