mlxsw: core_thermal: Remove unnecessary assignments

mlxsw: core_thermal: Remove unnecessary assignments

Setting both pointers to NULL is unnecessary since the code never checks
whether these pointers are NULL or not. Remove the assignments.

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/ea646f5d7642fffd5393fa23650660ab8f77a511.1722345311.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>