default or selected kernelversion does not have config value CONFIG_HVC_ISERIES.
Result is shown for kernelversion 6.2.5

iSeries Hypervisor Virtual Console support

modulename: hvc_iseries.ko

configname: CONFIG_HVC_ISERIES

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>iSeries Hypervisor Virtual Console support
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
iSeries machines support a hypervisor virtual console.

source code:
drivers/tty/hvc/hvc_iseries.c