There it is, a memory mapped PCI config space but the firmware has not marked the memory as reserved. Instead it's still in the Conventional Memory block, which means a loader or kernel could incorrectly allocate memory into that space.
Scope (_SB.PCI0.HEC2)
{
Name (H2BR, 0xBFF01000) <---
Name (H2ST, 0x0B)
OperationRegion (NMFS, PCI_Config, 0x40, 0x04)
Field (NMFS, DWordAcc, NoLock, Preserve)
{
, 30,
DMEN, 1,
NMEN, 1
}
This is a firmware bug; it should be reported to the vendor to do the right thing with memory map. Maybe they have a BIOS update available.