nvmem: imx-ocotp: add support for post processing

Add .cell_post_process callback for imx-ocotp to deal with MAC address,
since MAC address need to be reversed byte for some i.MX SoCs.

Tested-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211013131957.30271-4-srinivas.kandagatla@linaro.org


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