mb/asrock/b75m-itx: Move subsystemid from NIC to PCIe root port 4

As a follow-up to commit 1a591d0c4460 (mb/asrock/b75m-itx: Make NIC a
child device below PCIe port 4), this change corrects the subsystemid
being incorrectly applied to the Realtek NIC instead of the PCIe root
port.

Change-Id: Ib6fb8bf808132c008846d8ca9acde0eef277765c
Signed-off-by: Kevin Keijzer <kevin@quietlife.nl>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73930
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/mainboard/asrock/b75m-itx/devicetree.cb b/src/mainboard/asrock/b75m-itx/devicetree.cb
index 062a512..5f45ffe 100644
--- a/src/mainboard/asrock/b75m-itx/devicetree.cb
+++ b/src/mainboard/asrock/b75m-itx/devicetree.cb
@@ -49,9 +49,8 @@
 			device pci 1c.1 off end # PCIe Port #2
 			device pci 1c.2 off end # PCIe Port #3
 			device pci 1c.3 on  # PCIe Port #4, Realtek PCIe GbE Controller
-				device pci 00.0 on  # PCI 10ec:8168
-					subsystemid 0x1849 0x1e16
-				end
+				subsystemid 0x1849 0x1e16
+				device pci 00.0 on end # PCI 10ec:8168
 			end
 			device pci 1c.4 off end # PCIe Port #5
 			device pci 1c.5 on  # PCIe Port #6