This reverts f154a718 ("PCI: Add ACS quirk for Intel 300 series").

It turns out that erratum "PCH PCIe* Controller Root Port (ACSCTLR) Appear
As Read Only" has been fixed in 300 series chipsets, even though the
datasheet [1] claims otherwise.  To make ACS work properly on 300 series
root ports, revert the faulty commit.

[1] https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/300-series-c240-series-chipset-pch-spec-update.pdf

Fixes: f154a718 ("PCI: Add ACS quirk for Intel 300 series")
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org	# v4.18+