esp32: SEGGER SystemView Tracing Support

Implements support for system level traces compatible with SEGGER
SystemView tool on top of ESP32 application tracing module.
That kind of traces can help to analyse program's behaviour.
SystemView can show timeline of tasks/ISRs execution, context switches,
statistics related to the CPUs' load distribution etc.

Also this commit adds useful feature to ESP32 application tracing module:
 - Trace data buffering is implemented to handle temporary peaks of events load

components/esp32/include/esp_intr_alloc.h

@@ -77,6 +77,9 @@ extern "C" {
 
 /**@}*/
 
+// This is used to provide SystemView with positive IRQ IDs, otherwise sheduler events are not shown properly
+#define ETS_INTERNAL_INTR_SOURCE_OFF		(-ETS_INTERNAL_PROFILING_INTR_SOURCE)
+
 typedef void (*intr_handler_t)(void *arg); 
 
 
@@ -221,7 +224,6 @@ int esp_intr_get_cpu(intr_handle_t handle);
  */
 int esp_intr_get_intno(intr_handle_t handle);
 
-
 /**
  * @brief Disable the interrupt associated with the handle
  *