mlxsw: minimal: fix potential memory leak in mlxsw_m_linecards_init

mlxsw: minimal: fix potential memory leak in mlxsw_m_linecards_init

The line cards array is not freed in the error path of
mlxsw_m_linecards_init(), which can lead to a memory leak. Fix by
freeing the array in the error path, thereby making the error path
identical to mlxsw_m_linecards_fini().

Fixes: 01328e23a476 ("mlxsw: minimal: Extend module to port mapping with slot index")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20230630012647.1078002-1-shaozhengchao@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>