add event-driven framework

see examples/event_driven_at_module and examples/event_driven_hello_world, demo project: TencentOS-tiny\board\TencentOS_tiny_EVB_MX\KEIL\event_driven_hello_world

kernel/evtdrv/include/tos_evtdrv_err.h

@@ -0,0 +1,20 @@
+#ifndef _TOS_EVTDRV_ERR_H_
+#define  _TOS_EVTDRV_ERR_H_
+
+typedef enum evtdrv_err_en {
+    EVTDRV_ERR_NONE                 = 0x0u,
+    EVTDRV_ERR_MEM_ALLOC_FAILED     = 0x1u,
+    EVTDRV_ERR_PTR_NULL             = 0x2u,
+    EVTDRV_ERR_MSG_BUSY             = 0x3u,
+    EVTDRV_ERR_TASK_INVALID         = 0x4u,
+    EVTDRV_ERR_MMHEAP_NOT_ENABLED   = 0x5u,
+
+    EVTDRV_ERR_EVENT_INVALID         = 0x10u,
+    EVTDRV_ERR_EVENT_OVERFLOW       = 0x11u,
+
+    EVTDRV_ERR_TIMER_ALREADY_EXIST   = 0x20u,
+    EVTDRV_ERR_TIMER_INACTIVE       = 0x21u,
+} evtdrv_err_t;
+
+#endif
+