platform/mellanox: Remove redundant 'NULL' check

Remove 'NULL' check for 'data->hpdev.client' in error flow of
mlxreg_lc_probe(). It cannot be 'NULL' at this point.

Fixes: b4b830a3  ("platform/mellanox: mlxreg-lc: Fix error flow and extend verbosity")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/20220823201937.46855-5-vadimp@nvidia.com


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