Sub: move should_log check of log bitmask into DataFlash

ArduSub/Sub.cpp

@@ -21,7 +21,7 @@ const AP_HAL::HAL& hal = AP_HAL::get_HAL();
   constructor for main Sub class
  */
 Sub::Sub(void) :
-    DataFlash {FIRMWARE_STRING},
+    DataFlash {FIRMWARE_STRING, g.log_bitmask},
           mission(ahrs,
                   FUNCTOR_BIND_MEMBER(&Sub::start_command, bool, const AP_Mission::Mission_Command &),
                   FUNCTOR_BIND_MEMBER(&Sub::verify_command_callback, bool, const AP_Mission::Mission_Command &),

ArduSub/system.cpp

@@ -291,10 +291,7 @@ bool Sub::optflow_position_ok()
 bool Sub::should_log(uint32_t mask)
 {
 #if LOGGING_ENABLED == ENABLED
-    if (!(mask & g.log_bitmask)) {
+    if (!DataFlash.should_log(mask)) {
-        return false;
-    }
-    if (!DataFlash.should_log()) {
         return false;
     }
     start_logging();