ec/kontron/it8516e/acpi: Replace Multiply(a,b,c) with ASL 2.0 syntax

Replace `Multiply (a, b, c)` with `c = a * b`.

Change-Id: I81e976de964f6ae3528884debaf2b24ddf8ed28a
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60648
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Sean Rhodes <sean@starlabs.systems>

src/ec/kontron/it8516e/acpi/pm_channels.asl

@@ -35,7 +35,7 @@ Device (PM1) {
 		If (And (Local0, EC_ERROR_MASK)) {
 			Return (0)
 		}
-		Multiply (Local0, 10, Local0)	/* Convert to 10th °C */
+		Local0 *= 10
 		Return (Local0 + 2732)	/* Return as 10th Kelvin */
 	}
 }