net/mlx5e: RX, Fix wrong early return in receive queue poll

When the completion queue of the RQ is empty, do not immediately return.
If left-over decompressed CQEs (from the previous cycle) were processed,
need to go to the finalization part of the poll function.

Bug exists only when CQE compression is turned ON.

This solves the following issue:
mlx5_core 0000:82:00.1: mlx5_eq_int:544:(pid 0): CQ error on CQN 0xc08, syndrome 0x1
mlx5_core 0000:82:00.1 p4p2: mlx5e_cq_error_event: cqn=0x000c08 event=0x04

Fixes: 4b7dfc99 ("net/mlx5e: Early-return on empty completion queues")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>