default or selected kernelversion does not have config value CONFIG_DRM_DP_AUX_BUS.
Result is shown for kernelversion 6.9.9

CONFIG_DRM_DP_AUX_BUS (not configurable)

modulename: drm_dp_aux_bus.ko

configname: CONFIG_DRM_DP_AUX_BUS

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
└─>Device Tree and Open Firmware support
└─>DRM_DP_AUX_BUS
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
source code:
drivers/gpu/drm//display/drm_dp_aux_bus.c
depends
CONFIG_DRM
CONFIG_HAS_IOMEM
CONFIG_COMPILE_TEST or CONFIG_OF