CONFIG_MTD_OBSOLETE_CHIPS is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
default or selected kernelversion does not have config value CONFIG_MTD_OBSOLETE_CHIPS.
Result is shown for kernelversion 5.4.123

CONFIG_MTD_OBSOLETE_CHIPS (not configurable)

configname: CONFIG_MTD_OBSOLETE_CHIPS

Linux Kernel Configuration
└─>MTD_OBSOLETE_CHIPS
In linux kernel since version 2.6.12  
This option does not enable any code directly, but will allow you to
select some other chip drivers which are now considered obsolete,
because the generic CONFIG_JEDEC_PROBE code above should now detect
the chips which are supported by these drivers, and allow the generic
CFI-compatible drivers to drive the chips. Say 'N' here unless you have
already tried the CONFIG_JEDEC_PROBE method and reported its failure
to the MTD mailing list at <linux-mtd@lists.infradead.org>