dap_dp_init: remove loop

dap_dp_init: remove loop

current loop sounds to me like 'we don't know what we do, let's do it ten times, maybe we will have luck'.
should be enough to 'ping' debug port using reading CRTL_STAT.

tested on cortex-a8, snapdragon, jetson k1, cortex-r5, cortex-r4

Change-Id: Ibc62ac1eca06c141f4fccd5de7b11350ca1f35fd
Signed-off-by: Jiri Kastner <cz172638@gmail.com>
Tested-by: Jiri Kastner <cz172638@gmail.com>
Reviewed-on: http://openocd.zylin.com/3193
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-by: Liviu Dudau <liviu@dudau.co.uk>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>