jtag: drivers: cmsis-dap: fix operation with SAMD10 Xplained board

Change-Id: I9164edeb83c9a9106e74798e98b9517177e83358
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/3856


Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>