update psb_drm.h symbolic link

Change-Id: I7c4526f9ff117072980bf6cc8e766c350a5c0c6f
Signed-off-by: Jack Ren <jack.ren@intel.com>
diff --git a/psb_drm.h b/psb_drm.h
index 32b909b..48ac8dc 120000
--- a/psb_drm.h
+++ b/psb_drm.h
@@ -1 +1 @@
-../linux-2.6/drivers/gpu/drm/mrst/drv/psb_drm.h
\ No newline at end of file
+../linux-2.6/drivers/staging/mrst/drv/psb_drm.h
\ No newline at end of file