default or selected kernelversion does not have config value CONFIG_DEFXX_MMIO.
Result is shown for kernelversion 6.8.2

Use MMIO instead of IOP

configname: CONFIG_DEFXX_MMIO

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Use MMIO instead of IOP
In linux kernel since version 2.6.21.1 (release Date: 2007-04-27)  
This instructs the driver to use EISA or PCI memory-mapped I/O
(MMIO) as appropriate instead of programmed I/O ports (IOP).
Enabling this gives an improvement in processing time in parts
of the driver, but it requires a memory window to be configured
for EISA (DEFEA) adapters that may not always be available.
Conversely some PCIe host bridges do not support IOP, so MMIO
may be required to access PCI (DEFPA) adapters on downstream PCI
buses with some systems. TURBOchannel does not have the concept
of I/O ports, so MMIO is always used for these (DEFTA) adapters.

If unsure, say N.