Rally: fix compile warnings re float constants

libraries/AP_Rally/AP_Rally.cpp

@@ -13,16 +13,16 @@ StorageAccess AP_Rally::_storage(StorageManager::StorageRally);
 // ArduCopter/defines.h sets this, and this definition will be moved into ArduPlane/defines.h when that is patched to use the lib
 #ifdef APM_BUILD_DIRECTORY
   #if APM_BUILD_TYPE(APM_BUILD_ArduCopter)
-    #define RALLY_LIMIT_KM_DEFAULT 0.3
+    #define RALLY_LIMIT_KM_DEFAULT 0.3f
   #elif APM_BUILD_TYPE(APM_BUILD_ArduPlane)
-    #define RALLY_LIMIT_KM_DEFAULT 5.0
+    #define RALLY_LIMIT_KM_DEFAULT 5.0f
   #elif APM_BUILD_TYPE(APM_BUILD_APMrover2)
-    #define RALLY_LIMIT_KM_DEFAULT 0.5
+    #define RALLY_LIMIT_KM_DEFAULT 0.5f
   #endif
 #endif  // APM_BUILD_DIRECTORY
 
 #ifndef RALLY_LIMIT_KM_DEFAULT
-#define RALLY_LIMIT_KM_DEFAULT 1.0
+#define RALLY_LIMIT_KM_DEFAULT 1.0f
 #endif
 
 const AP_Param::GroupInfo AP_Rally::var_info[] PROGMEM = {