platform/mellanox: nvsw-sn2201: fix error code in nvsw_sn2201_create_static_devices()

This should return PTR_ERR() instead of IS_ERR().  Also "dev->client"
has been set to NULL by this point so it returns 0/success so preserve
the error code earlier.

Fixes: 662f2482 ("platform/mellanox: Add support for new SN2201 system")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Michael Shych <michaelsh@nvidia.com>
Link: https://lore.kernel.org/r/YqmUGwmPK7cPolk/@kili


Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>