Revert "drvmgr: Move bsp_driver_level_hook() calls"

The --enable-drvmgr configure option controls the driver manager startup
and not if the driver manager is present or not.  Presence of the driver
manager is determined by the architecture (only available on sparc so
far).

This reverts commit 61bbf9194f.

cpukit/libdrvmgr/drvmgr.c

@@ -68,15 +68,14 @@ void _DRV_Manager_init_level(int level)
 {
 	struct drvmgr *mgr = &drvmgr;
 
-	if (mgr->level < level) {
-		/* Set new Level */
-		mgr->level = level;
+	if (mgr->level >= level)
+		return;
 
-		/* Initialize buses and devices into this new level */
-		drvmgr_init_update();
-	}
+	/* Set new Level */
+	mgr->level = level;
 
-	bsp_driver_level_hook(level);
+	/* Initialize buses and devices into this new level */
+	drvmgr_init_update();
 }
 
 /* Initialize Data structures of the driver manager and call driver

cpukit/sapi/src/exinit.c

@@ -190,6 +190,7 @@ static void rtems_initialize_device_drivers(void)
    *   - Install extra memory.
    */
   _DRV_Manager_init_level(1);
+  bsp_driver_level_hook(1);
   #endif
 
   /* Initialize I/O drivers. 
@@ -210,6 +211,7 @@ static void rtems_initialize_device_drivers(void)
    * for the first time.
    */
   _DRV_Manager_init_level(2);
+  bsp_driver_level_hook(2);
 
   /* Init Drivers to Level 3 
    * 
@@ -218,11 +220,13 @@ static void rtems_initialize_device_drivers(void)
    * API inited in level 2
    */
   _DRV_Manager_init_level(3);
+  bsp_driver_level_hook(3);
 
   /* Init Drivers to Level 4,
    * Init drivers that depend on services initialized in Level 3
    */
   _DRV_Manager_init_level(4);
+  bsp_driver_level_hook(4);
   #endif
 
   #if defined(RTEMS_MULTIPROCESSING)