iio:common:ssp_sensors: Fix an error handling path ssp_probe()

iio:common:ssp_sensors: Fix an error handling path ssp_probe()

If an error occurs after a successful mfd_add_devices() call, it should be
undone by a corresponding mfd_remove_devices() call, as already done in the
remove function.

Fixes: 50dd64d57eee ("iio: common: ssp_sensors: Add sensorhub driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>