default or selected kernelversion does not have config value CONFIG_SOUND_AU1550_AC97.
Result is shown for kernelversion 5.4.69

Au1550/Au1200 AC97 Sound

modulename: au1550_ac97.ko

configname: CONFIG_SOUND_AU1550_AC97

Linux Kernel Configuration
└─>Device Drivers
└─>Sound card support
└─>Open Sound System (DEPRECATED)
└─>Au1550/Au1200 AC97 Sound
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
source code:
sound/oss/