ec/smsc/mec1308/acpi: Replace Add(a,b) with ASL 2.0 syntax

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

Change-Id: I82a960f9b5748ccdde3c07b78963b44b8dbef37e
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60505
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>

src/ec/smsc/mec1308/acpi/battery.asl

@@ -158,7 +158,7 @@ Device (BAT0)
 			// See if within ~3% of full
 			ShiftRight (Local2, 5, Local3)
 			If (LGreater (Local1, Local2 - Local3) &&
-			          LLess (Local1, Add (Local2, Local3)))
+			          LLess (Local1, Local2 + Local3))
 			{
 				Store (Local2, Local1)
 			}