default or selected kernelversion does not have config value CONFIG_ZX296702_SPDIF.
Result is shown for kernelversion 6.4.14

ZX296702 spdif

modulename: zx296702-spdif.ko

configname: CONFIG_ZX296702_SPDIF

Linux Kernel Configuration
└─>Device Drivers
└─>Sound card support
└─>Advanced Linux Sound Architecture
└─>ALSA for SoC audio support
└─>ZX296702 spdif
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Say Y or M if you want to add support for codecs attached to the
zx296702 spdif interface

source code:
sound/soc//zte/zx296702-spdif.c