mb/asrock/h110m: Choose `CHIPSET_LOCKDOWN_COREBOOT`

The `chipset_lockdown` option defaults to `CHIPSET_LOCKDOWN_FSP` if
omitted. As most of the mainboards use `CHIPSET_LOCKDOWN_COREBOOT`,
choose it here as well for consistency.

Change-Id: I5ef61f3d931abdb740411d8c58048cf21185802c
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52094
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Maxim Polyakov <max.senia.poliak@gmail.com>

src/mainboard/asrock/h110m/devicetree.cb

@@ -42,6 +42,10 @@ chip soc/intel/skylake
 	# Send an extra VR mailbox command for the PS4 exit issue
 	register "SendVrMbxCmd" = "2"
 
+	register "common_soc_config" = "{
+		.chipset_lockdown = CHIPSET_LOCKDOWN_COREBOOT,
+	}"
+
 	device cpu_cluster 0 on
 		device lapic 0 on end
 	end