Err you read that wrong, its a PCI-E to PCI chip, it cant work in reverse.
(Title of page: PEX 8111 PCI Express-to-PCI Bridge)
Its like the PCI to ISA chips that are/were used to add ISA slots to a PCI design.
That said there are Xilinx designs for PCI-E controllers but I doubt we will see one in the Amiga any time soon.