mb/ibase/mb899/acpi: Convert platform.asl to ASL 2.0 syntax

It builds same binary for ibase/mb899 using BUILD_TIMELESS=1

Change-Id: I947c4228641abc38a5cd75e51fa2f096fda95d6f
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45280
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/ibase/mb899/acpi/platform.asl

@@ -20,12 +20,12 @@ Method(_WAK,1)
 	// was inserted while a sleep state was active.
 
 	// Are we going to S3?
-	If (LEqual(Arg0, 3)) {
+	If (Arg0 == 3) {
 		// ..
 	}
 
 	// Are we going to S4?
-	If (LEqual(Arg0, 4)) {
+	If (Arg0 == 4) {
 		// ..
 	}