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

DC support for Polaris and older ASICs


Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
└─>Display Engine Configuration
└─>DC support for Polaris and older ASICs
In linux kernel since version 4.9.8 (release Date: 2017-02-04)  
Choose this option to enable the new DC support for older asics
by default. This includes Polaris, Carrizo, Tonga, Bonaire,
and Hawaii.