Fixing mobile related implementations of DeviceManagerService SPI to be able to support newly added getProviderType method

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/android/AndroidDeviceManagerService.java

@@ -27,7 +27,14 @@ import java.util.List;
  */
 public class AndroidDeviceManagerService implements DeviceManagerService {
 
-	@Override
+    private static final String DEVICE_MANAGER_ANDROID = "android";
+
+    @Override
+    public String getProviderType() {
+        return DEVICE_MANAGER_ANDROID;
+    }
+
+    @Override
 	public void enrollDevice(Device device) throws DeviceManagementException {
 
 	}

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/ios/IOSDeviceManagerService.java

@@ -26,7 +26,15 @@ import java.util.List;
  * This represents the iOS implementation of DeviceManagerService. *
  */
 public class IOSDeviceManagerService implements DeviceManagerService {
-	@Override
+
+    private static final String DEVICE_MANAGER_IOS = "ios";
+
+    @Override
+    public String getProviderType() {
+        return DEVICE_MANAGER_IOS;
+    }
+
+    @Override
 	public void enrollDevice(Device device) throws DeviceManagementException {
 
 	}

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/windows/WindowsDeviceManagerService.java

@@ -25,8 +25,16 @@ import java.util.List;
 /**
  * This represents the Windows implementation of DeviceManagerService.
  */
-public class WindowsDeviceManagerService implements DeviceManagerService{
-	@Override
+public class WindowsDeviceManagerService implements DeviceManagerService {
+
+    private static final String DEVICE_MANAGER_WINDOWS = "windows";
+
+    @Override
+    public String getProviderType() {
+        return DEVICE_MANAGER_WINDOWS;
+    }
+
+    @Override
 	public void enrollDevice(Device device) throws DeviceManagementException {
 
 	}