Ignore ack received after DP_TARGETSEL write to prevent false error.
Inspired by Graham Sanderson's http://review.openocd.org/4935
Change-Id: I04fd77cde3244de250743d8c8bfb93ed26379385
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/6698
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>