EKF: use ECL printfs everywhere

- Changes all printfs to ECL printfs
- Add ECL_ERR.
- Include ecl.h where needed.
- Add forgotten pragma once.

ecl.h

@@ -36,11 +36,13 @@
  * Adapter / shim layer for system calls needed by ECL
  *
  */
+#pragma once
 
 #include <drivers/drv_hrt.h>
 #include <px4_log.h>
 
 #define ecl_absolute_time hrt_absolute_time
 #define ecl_elapsed_time hrt_elapsed_time
-#define ECL_WARN PX4_WARN
 #define ECL_INFO PX4_INFO
+#define ECL_WARN PX4_WARN
+#define ECL_ERR	 PX4_ERR