regulator: max8997: Fix using wrong dev argument at various places

Use &pdev->dev rather than iodev->dev for dev_err(), dev_warn() and dev_info().
Use &pdev->dev rather than iodev->dev for devm_kzalloc() and
of_get_regulator_init_data(), this fixes memory leak.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>