[BSP] Update xplorer4330 bsp.

Author: BernardXiong

bsp/xplorer4330/M0/SConstruct

@@ -5,7 +5,7 @@ import rtconfig
 if os.getenv('RTT_ROOT'):
     RTT_ROOT = os.getenv('RTT_ROOT')
 else:
-    RTT_ROOT = os.path.join(Dir('#').get_abspath(), '..', '..', 'rt-thread')
+    RTT_ROOT = os.path.join(Dir('#').get_abspath(), '..', '..', '..')
 
 sys.path = sys.path + [os.path.join(RTT_ROOT, 'tools')]
 from building import *