platform: mellanox: Fix a resource leak in an error handling path in probing flow

Fix missed resource deallocation in rollback flows.

Currently if an error occurs after a successful
mlxplat_i2c_main_init(), mlxplat_i2c_main_exit() call is missed in
rollback flow.
Thus, some resources are not de-allocated.

Move mlxplat_pre_exit() call from mlxplat_remove() into
mlxplat_i2c_main_exit().

Call mlxplat_i2c_main_exit() instead of calling mlxplat_pre_exit() in
mlxplat_probe() error handling flow.

Unregister 'priv->pdev_i2c' device in mlxplat_i2c_main_init() cleanup
flow if this device was successfully registered.

Fixes: 158cd832

 ("platform: mellanox: Split logic in init and exit flow")
Reported-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Closes: https://lore.kernel.org/lkml/70165032-796e-6f5c-6748-f514e3b9d08c@linux.intel.com/T/
Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20231005075616.42777-2-vadimp@nvidia.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>