makefile: fix the root path of OPENOCD_SCRIPT_ROOT

The openocd scripts root directory gets calculated improperly,
OPENOCD_EXECUTABLE_ROOT is the 'bin' folder, it's in the same
parent dirextory as 'script', so we need use '..' to get the
parent directory first.

fix issue #174

Signed-off-by: Jingru Wang <jingru@synopsys.com>

Author: wangnuannuan

options/toolchain/toolchain_gnu.mk

@@ -156,7 +156,7 @@ ifeq ($(findstring $(MAKECMDGOALS),run gui),)
 endif
 endif
 else
-    OPENOCD_SCRIPT_ROOT = $(OPENOCD_EXECUTABLE_ROOT)/share/openocd/scripts
+    OPENOCD_SCRIPT_ROOT = $(OPENOCD_EXECUTABLE_ROOT)/../share/openocd/scripts
 endif
 
 ## Don't change this line