IB/ipoib: Change number of TX wqe to 64

NAPI budget is 64 packets, while maximum polling size for
the send CQ is 16. Let's bring them in sync, so the NAPI
budget will be reused completely.

Cc: Kamal Heib <kamalh@mellanox.com>
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>