drivers/jlink: Revert old workaround

drivers/jlink: Revert old workaround

This workaround broke usage with at least the I.MX6Q.

The comment implies that talking to the J-Link dongle itself should
fail if the target isn't reset, which sounds really strange. I'm
guessing it just triggered another bug in OpenOCD or Segger FW which
might have been fixed since. Revert and wait and see if there are any
failure reports.

Tested with Kwikstik (J-Link + Kinetis K40), not with the mentioned
adapter.

Change-Id: I97f555efe079bd99c098bf483491d9509b2363ad
Signed-off-by: Roy Spliet <rspliet@mpi-sws.org>
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/2147
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>