jtag: drivers: stlink: remove unnecessary '\n' in LOG_* entries

Change-Id: Ia2dc3efc27b53334af4d85f9807abba0463c291b
Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Reviewed-on: http://openocd.zylin.com/2220
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>