clang-tidy: enable readability-delete-null-pointer and fix

.clang-tidy

@@ -87,7 +87,6 @@ Checks:          '*,
                   -readability-avoid-const-params-in-decls,
                   -readability-braces-around-statements,
                   -readability-container-size-empty,
-                  -readability-delete-null-pointer,
                   -readability-else-after-return,
                   -readability-function-size,
                   -readability-implicit-bool-cast,

src/lib/drivers/device/ringbuffer.cpp

@@ -53,9 +53,7 @@ RingBuffer::RingBuffer(unsigned num_items, size_t item_size) :
 
 RingBuffer::~RingBuffer()
 {
-	if (_buf != nullptr) {
+	delete[] _buf;
-		delete[] _buf;
-	}
 }
 
 unsigned

src/modules/airspeed_selector/airspeed_selector_main.cpp

@@ -182,9 +182,7 @@ AirspeedModule::~AirspeedModule()
 
 	perf_free(_perf_elapsed);
 
-	if (_airspeed_validator != nullptr) {
+	delete[] _airspeed_validator;
-		delete[] _airspeed_validator;
-	}
 }
 
 int

src/modules/events/send_event.cpp

@@ -81,13 +81,8 @@ SendEvent::SendEvent() : ModuleParams(nullptr)
 
 SendEvent::~SendEvent()
 {
-	if (_status_display != nullptr) {
+	delete _status_display;
-		delete _status_display;
+	delete _rc_loss_alarm;
-	}
-
-	if (_rc_loss_alarm != nullptr) {
-		delete _rc_loss_alarm;
-	}
 }
 
 int SendEvent::start()

src/modules/mavlink/mavlink_ftp.cpp

@@ -57,13 +57,8 @@ MavlinkFTP::MavlinkFTP(Mavlink *mavlink) :
 
 MavlinkFTP::~MavlinkFTP()
 {
-	if (_work_buffer1) {
+	delete[] _work_buffer1;
-		delete[] _work_buffer1;
+	delete[] _work_buffer2;
-	}
-
-	if (_work_buffer2) {
-		delete[] _work_buffer2;
-	}
 }
 
 unsigned

src/modules/mc_pos_control/mc_pos_control_main.cpp

@@ -297,9 +297,7 @@ MulticopterPositionControl::MulticopterPositionControl() :
 
 MulticopterPositionControl::~MulticopterPositionControl()
 {
-	if (_wv_controller != nullptr) {
+	delete _wv_controller;
-		delete _wv_controller;
-	}
 
 	perf_free(_cycle_perf);
 }

src/modules/uORB/uORBDeviceNode.cpp

@@ -66,9 +66,7 @@ uORB::DeviceNode::DeviceNode(const struct orb_metadata *meta, const uint8_t inst
 
 uORB::DeviceNode::~DeviceNode()
 {
-	if (_data != nullptr) {
+	delete[] _data;
-		delete[] _data;
-	}
 
 	CDev::unregister_driver_and_memory();
 }