nvmem: imx-ocotp: Improve logic to save many code lines

Several logic improvements to save many code lines:

 - no need to use goto;
 - no need to assign return value;
 - combine different conditions of return value into one line.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200511145042.31223-2-srinivas.kandagatla@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>