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

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

Change-Id: Ibd25a05f49f79e80592482a1b0532334f727af58
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70841
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/southbridge/intel/i82371eb/acpi/intx.asl

@@ -30,7 +30,7 @@ Device(intx) {						\
 							\
 	Method(_CRS ,0) {				\
 		CreateWordField(IRQB, 1, IRQN)		\
-		ShiftLeft(1, And(pinx, 0x0f), IRQN)	\
+		IRQN = 1 << And(pinx, 0x0f)		\
 		Return(IRQB)				\
 	}						\
 							\

src/southbridge/intel/i82371eb/acpi/pirq.asl

@@ -40,7 +40,7 @@ Device(intx) {						\
 							\
 	Method(_CRS ,0) {				\
 		CreateWordField(IRQB, 1, IRQN)		\
-		ShiftLeft(1, And(pinx, 0x0f), IRQN)	\
+		IRQN = 1 << And(pinx, 0x0f)		\
 		Return(IRQB)				\
 	}						\
 							\