qlcnic: Fix TSS/RSS ring validation logic.

o TSS/RSS ring validation does not take into account that either
  of these ring values can be 0. This patch fixes this validation
  and would fail set_channel operation if any of these ring value
  is 0. This regression was added as part of commit id
  34e8c406 ("qlcnic: refactor Tx/SDS
  ring calculation and validation in driver.")

Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>