Update AwsIotEndpointUtility.java (#580)

* Update AwsIotEndpointUtility.java

input endpoint -> XXXXXX.ats.iot.[region].amazonaws.com.cn

Region.getRegion: throw Cannot create enum from iot value!

* Update AwsIotEndpointUtility.java

Author: brandonbai

aws-android-sdk-iot/src/main/java/com/amazonaws/mobileconnectors/iot/AwsIotEndpointUtility.java

@@ -91,8 +91,8 @@ static Region getRegionFromIotEndpoint(String endpoint) {
         String endpointWithoutPort = stripPort(endpoint);
         validateIotEndpoint(endpointWithoutPort);
         String[] splits = splitEndpoint(endpointWithoutPort);
-
-        return Region.getRegion(Regions.fromName(splits[ENDPOINT_REGION_OFFSET]));
+        int offset = splits.length == ENDPOINT_CN_ATS_SPLIT_SIZE?(ENDPOINT_REGION_OFFSET+1):ENDPOINT_REGION_OFFSET;
+        return Region.getRegion(Regions.fromName(splits[offset]));
     }
 
     /**