CONFIG_HPAPCI is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

HP APCI serial support

configname: CONFIG_HPAPCI

Linux Kernel Configuration
└─>Character devices
└─>HP APCI serial support
In linux kernel since version 2.6.12  
If you want to use the internal "APCI" serial ports on an HP400
machine, say Y here.