RDMA/mlx5: Remove extra unlock on error path

The below commit lifted the locking out of this function but left this
error path unlock behind resulting in unbalanced locking. Remove the
missed unlock too.

Cc: stable@vger.kernel.org
Fixes: 62712228

 ("RDMA/mlx5: Add work to remove temporary entries from the cache")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Michael Guralnik <michaelgur@nvidia.com>
Link: https://lore.kernel.org/r/78090c210c750f47219b95248f9f782f34548bb1.1716900410.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>