add rival constants

data/string/rival_names.s

@@ -0,0 +1,11 @@
+.align 2
+.thumb
+.text
+
+.global name_rival_male
+name_rival_male:
+    .string LAN_DE "Noah"
+
+.global name_rival_female
+name_rival_female:
+    .string LAN_DE "Emma"