default or selected kernelversion does not have config value CONFIG_BLK_DEV_IDEDOUBLER.
Result is shown for kernelversion 5.3.7

Amiga IDE Doubler support (EXPERIMENTAL)

configname: CONFIG_BLK_DEV_IDEDOUBLER

Linux Kernel Configuration
└─>Device Drivers
└─>ATA/ATAPI/MFM/RLL support
└─>Amiga IDE Doubler support (EXPERIMENTAL)
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This feature provides support for the so-called `IDE doublers' (made
by various manufacturers, e.g. Eyetech) that can be connected to
the on-board IDE interface of some Amiga models. Using such an IDE
doubler, you can connect up to four instead of two IDE devices to
the Amiga's on-board IDE interface.

Note that the normal Amiga Gayle IDE driver may not work correctly
if you have an IDE doubler and don't enable this feature!

Say Y if you have an IDE doubler. The feature is enabled at kernel
runtime using the "gayle.doubler" kernel boot parameter.

depends
CONFIG_BLK_DEV_GAYLE
CONFIG_BLK_DEV_IDE
CONFIG_EXPERIMENTAL
CONFIG_IDE