mlxsw: core_thermal: Make mlxsw_thermal_module_{init, fini} symmetric

mlxsw_thermal_module_fini() de-initializes the module's thermal zone,
but mlxsw_thermal_module_init() does not initialize it. Make both
functions symmetric by moving the initialization of the module's thermal
zone to mlxsw_thermal_module_init().

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Link: https://patch.msgid.link/a661ad468f8ad0d7d533d8334e4abf61dfe34342.1722345311.git.petrm@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>