build: add helper/types.h to config.h

this header is used in numerous files and adding to config.h
simplifies its use globally.

Change-Id: Id724a9950b90504721233022c7fb5768e9bc5548
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/649


Tested-by: jenkins
Reviewed-by: Xiaofan <xiaofanc@gmail.com>