AP_NavEKF2: remove default clause in setAidingMode

All values from the enumeration should be handled in this switch; adding
a default will hide a compiler warning which may be useful.

libraries/AP_NavEKF2/AP_NavEKF2_Control.cpp

@@ -257,12 +257,9 @@ void NavEKF2_core::setAidingMode()
             rngBcnTimeout = true;
             gpsNotAvailable = true;
         }
-        }
-        break;
-
-    default:
         break;
     }
+    }
 
     // check to see if we are starting or stopping aiding and set states and modes as required
     if (PV_AidingMode != PV_AidingModePrev) {
@@ -332,9 +329,6 @@ void NavEKF2_core::setAidingMode()
             lastRngBcnPassTime_ms = imuSampleTime_ms;
             }
             break;
-
-        default:
-            break;
         }
 
         // Always reset the position and velocity when changing mode