CONFIG_CPU_SUBTYPE_SH7750 is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

Support SH7750 processor

modulename: setup-sh7750.ko

configname: CONFIG_CPU_SUBTYPE_SH7750

Processor sub-type selection
└─>Support SH7750 processor
In linux kernel since version 2.6.12  
Select SH7750 if you have a 200 Mhz SH-4 HD6417750 CPU.

source code:
arch/sh/kernel/cpu/sh4/setup-sh7750.c
selects
CONFIG_CPU_SH4

is selected by
CONFIG_SH_SOLUTION_ENGINE