mb/purism/librem_skl: Convert to use override devicetree

Since the variants' devicetrees are almost identical, convert to
using an overridetree setup for simplicity.

Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
Change-Id: I3dac62a649e12ea2498d3ecafe03fd0d62af5f2b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40911
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/mainboard/purism/librem_skl/variants/librem13v2/overridetree.cb b/src/mainboard/purism/librem_skl/variants/librem13v2/overridetree.cb
new file mode 100644
index 0000000..18ce220
--- /dev/null
+++ b/src/mainboard/purism/librem_skl/variants/librem13v2/overridetree.cb
@@ -0,0 +1,17 @@
+chip soc/intel/skylake
+
+	register "usb2_ports[0]" = "USB2_PORT_TYPE_C(OC_SKIP)"	# Type-C Port
+	register "usb2_ports[1]" = "USB2_PORT_MID(OC0)"		# Type-A Port (right)
+	register "usb2_ports[2]" = "USB2_PORT_MID(OC_SKIP)"	# Bluetooth
+	register "usb2_ports[3]" = "USB2_PORT_FLEX(OC_SKIP)"	# Camera
+	register "usb2_ports[5]" = "USB2_PORT_FLEX(OC2)"	# Type-A Port (left)
+	register "usb2_ports[6]" = "USB2_PORT_MID(OC_SKIP)"	# SD
+
+	# OC1 should be for Type-C but it seems to not have been wired, according to
+	# the available schematics, even though it is labeled as USB_OC_TYPEC.
+	register "usb3_ports[0]" = "USB3_PORT_DEFAULT(OC_SKIP)"	# Type-C Port
+	register "usb3_ports[1]" = "USB3_PORT_DEFAULT(OC0)"	# Type-A Port (right)
+	register "usb3_ports[2]" = "USB3_PORT_DEFAULT(OC_SKIP)"	# Type-C Port
+
+	device domain 0 on end
+end