Fix OEM ID in ASL tests

Turns out we had a OEM ID that was too long (must be a maximum of 6 chars)
but the old version of the compiler never picked it up. Also changed where
PCI0 is expected to be in the namespace to test nested scopes.

tests/scopes.asl

@@ -1,7 +1,7 @@
-DefinitionBlock("scopes.aml", "DSDT", 1, "RSOSDEV", "SCOPES", 1) {
+DefinitionBlock("scopes.aml", "DSDT", 1, "RSACPI", "SCOPES", 1) {
 	Scope(_SB) {
 		Name(X, 320)
-		Device(\PCI0) {
+		Device(PCI0) {
 			Name(Y, 15)
 			Scope(\) {
 				Name(Z, 413)