CONFIG_ARCH_QCOM is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64

Qualcomm Platforms

configname: CONFIG_ARCH_QCOM

Linux Kernel Configuration
└─>Platform selection
└─>Qualcomm Platforms
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This enables support for the ARMv8 based Qualcomm chipsets.