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

Platform driver for IDE interfaces

modulename: ide_platform.ko

configname: CONFIG_BLK_DEV_PLATFORM

Linux Kernel Configuration
└─>Device Drivers
└─>ATA/ATAPI/MFM/RLL support (DEPRECATED)
└─>Platform driver for IDE interfaces
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
This is the platform IDE driver, used mostly for Memory Mapped
IDE devices, like Compact Flashes running in True IDE mode.

If unsure, say N.

source code:
depends
CONFIG_IDE