CONFIG_HOTPLUG_PCI_S390 is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

System z PCI Hotplug Support

modulename: s390_pci_hpc.ko

configname: CONFIG_HOTPLUG_PCI_S390

Linux Kernel Configuration
└─>Device Drivers
└─>PCI support
└─>Support for PCI Hotplug
└─>System z PCI Hotplug Support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Say Y here if you want to use the System z PCI Hotplug
driver for PCI devices. Without this driver it is not
possible to access stand-by PCI functions nor to deconfigure
PCI functions.

When in doubt, say Y.

source code: