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 <[e-mail]>
Reviewed-by: Nuno Sá <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/common/ssp_sensors/ssp_dev.c

···
 	ret = spi_setup(spi);
 	if (ret < 0) {
 		dev_err(&spi->dev, "Failed to setup spi\n");
-		return ret;
+		goto err_setup_spi;
 	}
 
 	data->fw_dl_state = SSP_FW_DL_STATE_NONE;
···
 err_setup_irq:
 	mutex_destroy(&data->pending_lock);
 	mutex_destroy(&data->comm_lock);
+err_setup_spi:
+	mfd_remove_devices(&spi->dev);
 
 	dev_err(&spi->dev, "Probe failed!\n");