net/mlx5: Release resource on error flow

mainline inclusion
from mainline-5.0
commit 69811496
category: bugfix
bugzilla: 6104
CVE: NA

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Fix reference counting leakage when the event handler aborts due to an
unsupported event for the resource type.

Fixes: a14c2d4b ("net/mlx5_core: Warn on unsupported events of QP/RQ/SQ")
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Keefe LIU <liuqifa@huawei.com>
Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>