rtems: Move rtems_task_priority definition

This type is not only used by Task Manager directives.  This is a
preparation to move the rtems_scheduler_*() directives from
<rtems/rtems/tasks.h> to a new <rtems/rtems/scheduler.h>.

cpukit/include/rtems/rtems/sem.h

@@ -58,7 +58,6 @@
 #include <rtems/rtems/attr.h>
 #include <rtems/rtems/options.h>
 #include <rtems/rtems/status.h>
-#include <rtems/rtems/tasks.h>
 #include <rtems/rtems/types.h>
 
 #ifdef __cplusplus

cpukit/include/rtems/rtems/timer.h

@@ -59,7 +59,6 @@
 #include <stddef.h>
 #include <rtems/rtems/attr.h>
 #include <rtems/rtems/status.h>
-#include <rtems/rtems/tasks.h>
 #include <rtems/rtems/types.h>
 #include <rtems/score/watchdogticks.h>
 

cpukit/include/rtems/rtems/types.h

@@ -7,8 +7,8 @@
  */
 
 /*
- * Copyright (C) 2009, 2020 embedded brains GmbH (http://www.embedded-brains.de)
- * Copyright (C) 2006, 2008 On-Line Applications Research Corporation (OAR)
+ * Copyright (C) 2009, 2021 embedded brains GmbH (http://www.embedded-brains.de)
+ * Copyright (C) 1988, 2017 On-Line Applications Research Corporation (OAR)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -254,6 +254,15 @@ typedef uint32_t rtems_name;
   typedef MP_packet_Prefix rtems_packet_prefix;
 #endif
 
+/* Generated from spec:/rtems/type/if/priority */
+
+/**
+ * @ingroup RTEMSAPIClassicTypes
+ *
+ * @brief This integer type represents task priorities of the Classic API.
+ */
+typedef uint32_t rtems_task_priority;
+
 /* Generated from spec:/rtems/type/if/time-of-day */
 
 /**