default or selected kernelversion does not have config value CONFIG_DRM_AMD_DC_HDCP.
Result is shown for kernelversion 6.9.2

Enable HDCP support in DC


Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
└─>Display Engine Configuration
└─>Enable HDCP support in DC
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Choose this option if you want to support HDCP authentication.