skl mainboards/dt: Move serirq setting into LPC device scope

Change-Id: I84da5365907664ce223dec4adb22a8f1a6e2a144
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83188
Reviewed-by: Jonathon Hall <jonathon.hall@puri.sm>
Reviewed-by: Marvin Evers <marvin.n.evers@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>
Reviewed-by: Erik van den Bogaert <ebogaert@eltan.com>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
diff --git a/src/mainboard/libretrend/lt1000/devicetree.cb b/src/mainboard/libretrend/lt1000/devicetree.cb
index 02c3538..2ebc6702 100644
--- a/src/mainboard/libretrend/lt1000/devicetree.cb
+++ b/src/mainboard/libretrend/lt1000/devicetree.cb
@@ -9,8 +9,6 @@
 
 	register "eist_enable" = "1"
 
-	register "serirq_mode" = "SERIRQ_CONTINUOUS"
-
 	# Set the Thermal Control Circuit (TCC) activation value to 95C
 	# even though FSP integration guide says to set it to 100C for SKL-U
 	# (offset at 0), because when the TCC activates at 100C, the CPU
@@ -170,6 +168,8 @@
 		device ref pcie_rp11	on  end
 		device ref pcie_rp12	on  end
 		device ref lpc_espi	on
+			register "serirq_mode" = "SERIRQ_CONTINUOUS"
+
 			register "gen1_dec" = "0x007c0a01" # EC 0xa00-0xa7f
 			register "gen2_dec" = "0x000c03e1" # COM3 port 0x3e0 - 0x3ef
 			register "gen3_dec" = "0x00fc02e1" # COM2/4/5/6 ports 0x2e0 - 0x2ff