CONFIG_CPU_V7M is not available for the selected architecture x86.
Result is shown for architecture arm

CONFIG_CPU_V7M (not configurable)

modulename: proc-v7m.ko

configname: CONFIG_CPU_V7M

Linux Kernel Configuration
└─>CPU_V7M
In linux kernel since version 3.10 (release Date: 2013-06-30)
source code:
/arch/arm/mm/

is selected by
CONFIG_THUMB2_KERNEL