default or selected kernelversion does not have config value CONFIG_ION_HISI.
Result is shown for kernelversion 6.4.14

Ion for Hisilicon

configname: CONFIG_ION_HISI

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Android
└─>Ion Memory Manager
└─>Ion for Hisilicon
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Choose this option if you wish to use ion on Hisilicon Platform.