AP_NavEKF2: fixed gaps in EKF logging

timestamps should not be static as otherwise some lanes will not be
logged

libraries/AP_NavEKF2/AP_NavEKF2_Logging.cpp

@@ -252,7 +252,6 @@ void NavEKF2_core::Log_Write_Beacon(uint64_t time_us)
 void NavEKF2_core::Log_Write_Timing(uint64_t time_us)
 {
     // log EKF timing statistics every 5s
-    static uint32_t lastTimingLogTime_ms = 0;
     if (AP::dal().millis() - lastTimingLogTime_ms <= 5000) {
         return;
     }

libraries/AP_NavEKF2/AP_NavEKF2_core.h

@@ -1178,6 +1178,9 @@ private:
     uint8_t EKFGSF_yaw_reset_count;         // number of emergency yaw resets performed
     bool EKFGSF_run_filterbank;             // true when the filter bank is active
 
+    // logging timestamps
+    uint32_t lastTimingLogTime_ms;
+
     // logging functions shared by cores:
     void Log_Write_NKF1(uint64_t time_us) const;
     void Log_Write_NKF2(uint64_t time_us) const;