mb/hp/280_g2: Restore comments documenting root port devices

While transitioning the devicetree to make use of the chipset
devicetree, commit 3b5b9f4c543c ("mb/hp/280_g2: Make use of the chipset
devicetree") removed useful comments documenting the endpoints of the
root ports. Restore them.

Change-Id: I178cb472a8f40baaccc30514689bda2730dfa9dc
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79153
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/mainboard/hp/280_g2/devicetree.cb b/src/mainboard/hp/280_g2/devicetree.cb
index d6c8bc0..3b25a42 100644
--- a/src/mainboard/hp/280_g2/devicetree.cb
+++ b/src/mainboard/hp/280_g2/devicetree.cb
@@ -64,12 +64,14 @@
 		end
 		device ref uart2	on	end
 		device ref pcie_rp5	on
+			# IT8893E PCI Bridge
 			register "PcieRpEnable[4]"			= "1"
 			register "PcieRpLtrEnable[4]"			= "1"
 			register "PcieRpAdvancedErrorReporting[4]"	= "1"
 			register "PcieRpClkSrcNumber[4]"		= "11"
 		end
 		device ref pcie_rp6	on
+			# PCIe x1 slot
 			register "PcieRpEnable[5]"			= "1"
 			register "PcieRpHotPlug[5]"			= "1"
 			register "PcieRpLtrEnable[5]"			= "1"
@@ -77,12 +79,14 @@
 			register "PcieRpClkSrcNumber[5]"		= "6"
 		end
 		device ref pcie_rp7	on
+			# RTL8111 GbE NIC
 			register "PcieRpEnable[6]"			= "1"
 			register "PcieRpLtrEnable[6]"			= "1"
 			register "PcieRpAdvancedErrorReporting[6]"	= "1"
 			register "PcieRpClkSrcNumber[6]"		= "10"
 		end
 		device ref pcie_rp8	on
+			# M.2 2230 slot
 			register "PcieRpEnable[7]"			= "1"
 			register "PcieRpHotPlug[7]"			= "1"
 			register "PcieRpLtrEnable[7]"			= "1"