mb/starlabs/labtop: Remove unnecessary return value from MWAK

Don't return 0x00 when running MWAK as it is not needed.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: Ic62eab8ae5319aff37c61fc29d701d9a36ada919
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62635
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/mainboard/starlabs/labtop/acpi/sleep.asl

@@ -8,5 +8,4 @@ Method (MPTS, 1, NotSerialized)
 Method (MWAK, 1, NotSerialized)
 {
 	RWAK (Arg0)
-	Return (0x00)
 }