ec/lenovo/h8/acpi: Replace Add(a,b,c) with ASL 2.0 syntax

Replace `Add (a, b, c)` with `c = a + b`.

Change-Id: Ibbc0831e688b62d7ed0dec5e4b7224688ed0ae6d
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60492
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>

src/ec/lenovo/h8/acpi/thermal.asl

@@ -12,7 +12,7 @@ Scope(\_TZ)
 	Method(C2K, 1, NotSerialized)
 	{
 		Multiply(Arg0, 10, Local0)
-		Add (Local0, 2732, Local0)
+		Local0 += 2732
 		if (LLessEqual(Local0, 2732)) {
 			Return (3000)
 		}

src/ec/lenovo/h8/acpi/thinkpad.asl

@@ -37,13 +37,13 @@ Device (HKEY)
 		Store (BTN, Local0)
 		If (LNotEqual (Local0, Zero)) {
 			Store (Zero, BTN)
-			Add (Local0, 0x1000, Local0)
+			Local0 += 0x1000
 			Return (Local0)
 		}
 		Store (BTAB, Local0)
 		If (LNotEqual (Local0, Zero)) {
 			Store (Zero, BTAB)
-			Add (Local0, 0x5000, Local0)
+			Local0 += 0x5000
 			Return (Local0)
 		}
 		Return (Zero)