sb/intel/i82801gx: Add common LPC decode code

Generic LPC decode ranges can now be set from the devicetree.

Change-Id: I1065ec770ad3a743286859efa39dca09ccb733a1
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36700
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/mainboard/roda/rk886ex/devicetree.cb b/src/mainboard/roda/rk886ex/devicetree.cb
index 0ceef6a..5bce304 100644
--- a/src/mainboard/roda/rk886ex/devicetree.cb
+++ b/src/mainboard/roda/rk886ex/devicetree.cb
@@ -62,6 +62,10 @@
 			register "ide_enable_primary" = "0x1"
 			register "ide_enable_secondary" = "0x0"
 
+			register "gen1_dec" = "0x001c02e1" # COM3, COM4
+			register "gen2_dec" = "0x00fc0601" # ??
+			register "gen3_dec" = "0x00040069" # EC decode ??
+
 			device pci 1b.0 off end # High Definition Audio
 			device pci 1c.0 on end # PCIe port 1
 			device pci 1c.1 off end # PCIe port 2