qede: Reset statistics on explicit down

Adding the necessary logic to prevet statistics reset
on inner-reload introduced a bug, and now statistics
are reset only when re-probing the driver.

Fixes: a0d26d5a ("qed*: Don't reset statistics on inner reload")
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>