default or selected kernelversion does not have config value CONFIG_MTD_ALCHEMY.
Result is shown for kernelversion 5.4.194
AMD Alchemy Pb1xxx/Db1xxx/RDK MTD support
modulename: alchemy-flash.ko
configname: CONFIG_MTD_ALCHEMY
Linux Kernel Configuration
└─>Device Drivers
└─>Memory Technology Device (MTD) support
└─>Mapping drivers for chip access
└─>AMD Alchemy Pb1xxx/Db1xxx/RDK MTD support
In linux kernel since version 2.6.20 (release Date: 2007-02-04)
Flash memory access on AMD Alchemy Pb/Db/RDK Reference Boards