Add CMSIS-DAP information to the READMEs.

Change-Id: I8c87d559adf07b0f0702fe9d388f26bf046bcb8b
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/1880


Tested-by: jenkins
Reviewed-by: Xiaofan <xiaofanc@gmail.com>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>