libcutils: UNUSED argument warnings

Change-Id: Ie427d481298af8d911bb2b157ebba30954335354
diff --git a/libcutils/str_parms.c b/libcutils/str_parms.c
index 9e1d2dc..f1f3584 100644
--- a/libcutils/str_parms.c
+++ b/libcutils/str_parms.c
@@ -30,6 +30,8 @@
 
 #include <cutils/str_parms.h>
 
+#define UNUSED __attribute__((unused))
+
 struct str_parms {
     Hashmap *map;
 };
@@ -318,7 +320,7 @@
     return str;
 }
 
-static bool dump_entry(void *key, void *value, void *context)
+static bool dump_entry(void *key, void *value, void *context UNUSED)
 {
     ALOGI("key: '%s' value: '%s'\n", (char *)key, (char *)value);
     return true;