cfg: Added Nucleo-F411RE board config.

It supports STLink/V2-1 debug adapter.

Change-Id: Ifbc610cd68ec929608369e69d0b1395fe04956cd
Signed-off-by: Nemui Trinomius <nemuisan_kawausogasuki@live.jp>
Reviewed-on: http://openocd.zylin.com/2259
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>