mb/google/butterfly: Fix smbus subsystem ID

The smbus subsystem ID was inadvertently reversed when added in commit
a6076cfcfd ("mb/google/butterfly: override SMBus subsystem ID"), so
correct it.

TEST=build/boot Win10 on butterfly, verify touchpad driver functional.

Change-Id: If4a0eae06bbe4dcba893a42797e371bbf9f899b9
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82225
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/butterfly/devicetree.cb

@@ -101,7 +101,7 @@ chip northbridge/intel/sandybridge
 			end # LPC bridge
 			device ref sata1 on end # SATA Controller 1
 			device ref smbus on
-				subsystemid 0x04B4 0x18D1
+				subsystemid 0x18D1 0x04B4
 			end # SMBus
 			device ref sata2 off end # SATA Controller 2
 			device ref thermal on end # Thermal