iio: pressure: ms5611: Switch to fully devm_ managed registration.

All the remaining calls in probe() have devm_ equivalents so
switching to those allows the remove() callbacks to be deleted.
No functional change.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Tomasz Duszynski <tduszyns@gmail.com>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/20221016163409.320197-15-jic23@kernel.org


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>