utils: checkstyle: add keep-one-line-blocks

Enable --keep-one-line-blocks to prevent astyle from wanting to move
single inlined blocks to cover 4 lines such as:

-       virtual int init() { return 0; }
+       virtual int init()
+       {
+               return 0;
+       }

Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

utils/checkstyle.py

@@ -29,6 +29,7 @@ astyle_options = (
     '--pad-oper',
     '--align-pointer=name',
     '--align-reference=name',
+    '--keep-one-line-blocks',
     '--max-code-length=120'
 )