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

Replace `ShiftLeft (a, b)` with `a << b`.

Change-Id: I812b1ed9dcf3a5749b39a9beb9f870258ad6a0de
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70842
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/intel/cannonlake/acpi/xhci.asl b/src/soc/intel/cannonlake/acpi/xhci.asl
index 614268c..52fdcbe 100644
--- a/src/soc/intel/cannonlake/acpi/xhci.asl
+++ b/src/soc/intel/cannonlake/acpi/xhci.asl
@@ -19,7 +19,7 @@
 	Local0 = Arg1 + ((Arg0 - 1) * 0x10)
 
 	/* Map ((XMEM << 16) + Local0 in PSCR */
-	OperationRegion (PSCR, SystemMemory, ShiftLeft (Arg2, 16) + Local0, 0x10)
+	OperationRegion (PSCR, SystemMemory, (Arg2 << 16) + Local0, 0x10)
 	Field (PSCR, DWordAcc, NoLock, Preserve)
 	{
 		PSCT, 32,