qed: Tell QM the number of tasks

Driver doesn't pass the number of tasks to the QM init logic
which would cause back-pressure in scenarios requiring many tasks
[E.g., using max MRs] and thus reduced performance.

Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>