mb/hp/z220_series: Improve the port for z220_sff_workstation

- Move configs for PCIe ports not present on z220_sff_workstation
  from the devicetree.cb of base board to the overridetree.cb of
  z220_cmt_workstation.

- Add a note for ME/AMT Flash Override jumper, for it is hard to
  flash from OEM firmware either internally or externally without
  closing this jumper.

- Add a side note for similar HP Compaq Elite 8300 SFF.

Signed-off-by: Bill XIE <persmule@hardenedlinux.org>
Change-Id: I35d8b97f52a83910a61c12b1f7367ee7a19a9ad7
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65703
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/hp/z220_series/devicetree.cb b/src/mainboard/hp/z220_series/devicetree.cb
index 4611bec..ea8fad9 100644
--- a/src/mainboard/hp/z220_series/devicetree.cb
+++ b/src/mainboard/hp/z220_series/devicetree.cb
@@ -22,6 +22,7 @@
 		device pci 00.0 on  end	# Host bridge Host bridge
 		device pci 01.0 on  end	# PCIe Bridge for discrete graphics
 		device pci 02.0 on  end	# Internal graphics VGA controller
+		device pci 06.0 off end	# Extra x4 port on north bridge
 
 		chip southbridge/intel/bd82x6x # Intel Series 7 PCH
 			register "docking_supported" = "0"
@@ -47,8 +48,8 @@
 			device pci 1c.3 off end	# PCIe Port #4
 			device pci 1c.4 on  end	# PCIe Port #5
 			device pci 1c.5 off end	# PCIe Port #6
-			device pci 1c.6 on  end	# PCIe Port #7
-			device pci 1c.7 on  end	# PCIe Port #8
+			device pci 1c.6 off end	# PCIe Port #7
+			device pci 1c.7 off end	# PCIe Port #8
 			device pci 1d.0 on  end	# USB2 EHCI #1
 			device pci 1e.0 on  end	# PCI bridge
 			device pci 1f.0 on	# LPC bridge PCI-LPC bridge