default or selected kernelversion does not have config value CONFIG_PHY_CADENCE_DP.
Result is shown for kernelversion 6.9.8

Cadence MHDP DisplayPort PHY driver

modulename: phy-cadence-dp.ko

configname: CONFIG_PHY_CADENCE_DP

Linux Kernel Configuration
└─>Device Drivers
└─>PHY Subsystem
└─>Device Tree and Open Firmware support
└─>Cadence MHDP DisplayPort PHY driver
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Support for Cadence MHDP DisplayPort PHY.

source code:
drivers/phy/cadence//phy-cadence-dp.c