AP_Mount: Fix typos

libraries/AP_Mount/AP_Mount_Backend.h

@@ -94,7 +94,7 @@ protected:
     MAV_MOUNT_MODE get_mode(void) const { return _frontend.get_mode(_instance); }
 
     AP_Mount    &_frontend; // reference to the front end which holds parameters
-    AP_Mount::mount_state &_state;    // refernce to the parameters and state for this backend
+    AP_Mount::mount_state &_state;    // references to the parameters and state for this backend
     uint8_t     _instance;  // this instance's number
     Vector3f    _angle_ef_target_rad;   // desired earth-frame roll, tilt and vehicle-relative pan angles in radians
 };

libraries/AP_Mount/SoloGimbalEKF.cpp

@@ -109,7 +109,7 @@ void SoloGimbalEKF::RunEKF(float delta_time, const Vector3f &delta_angles, const
         FiltInit = true;
         hal.console->printf("\nSoloGimbalEKF Alignment Started\n");
 
-        // Don't run the filter in this timestep becasue we have already used the delta velocity data to set an initial orientation
+        // Don't run the filter in this timestep because we have already used the delta velocity data to set an initial orientation
         return;
     }
 

libraries/AP_Mount/SoloGimbal_Parameters.cpp

@@ -142,7 +142,7 @@ void SoloGimbal_Parameters::update()
         }
     }
 
-    // check for nonexistant parameters
+    // check for nonexistent parameters
     for(uint8_t i=0; i<MAVLINK_GIMBAL_NUM_TRACKED_PARAMS; i++) {
         if (!_params[i].seen && _params[i].fetch_attempts > _max_fetch_attempts) {
             _params[i].state = GMB_PARAMSTATE_NONEXISTANT;