tree: Replace ShiftRight(a,b,c) with ASL 2.0 syntax

Replace `ShiftRight (a, b, c)` with `c = a >> b`. One case was
simplified to just `a >> b`.

Change-Id: I889012b0a3067138e6f02d3fe8e97151effb5c2a
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70840
Reviewed-by: Caveh Jalali <caveh@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

src/ec/quanta/it8518/acpi/battery.asl

@@ -316,7 +316,7 @@ Device (BATX)
 			Local2 = SBRS
 
 			// See if within ~3% of full
-			ShiftRight (Local2, 5, Local3)
+			Local3 = Local2 >> 5
 			If (Local1 > Local2 - Local3 && Local1 < Local2 + Local3)
 			{
 				Local1 = Local2