ide: Correct improper smart self test counter reset in ide core.

The SMART self test counter was incorrectly being reset to zero,
not 1. This had the effect that on every 21st SMART EXECUTE OFFLINE:
 * We would write off the beginning of a dynamically allocated buffer
 * We forgot the SMART history
Fix this.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Message-id: 1397336390-24664-1-git-send-email-benoit.canet@irqsave.net
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Cc: qemu-stable@nongnu.org
Acked-by: Kevin Wolf <kwolf@redhat.com>
[PMM: tweaked commit message as per suggestions from Markus]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
