nvmem: imx-ocotp: fix usage of "dev" pointers

Assign the correct dev pointer to struct ocotp_priv during probe. This
is needed to display dev_* messages correctly. Furthermore harmonize
the usage of dev (instead of &pdev->dev) in the probe function.

Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>