net/mlx4_en: Fix adaptive moderation cq update

When turning on adaptive_rx under adaptive moderation, the CQ's moderation
count wasn't updated according to rx_frames which resulted in too many
interrupts and bandwidth drop.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>