default or selected kernelversion does not have config value CONFIG_XZ_DEC_IA64.
Result is shown for kernelversion 6.9.9

IA-64 BCJ filter decoder

configname: CONFIG_XZ_DEC_IA64

Linux Kernel Configuration
└─>Library routines
└─>IA-64 BCJ filter decoder
In linux kernel since version 2.6.38 (release Date: 2011-03-14)  

depends
CONFIG_XZ_DEC