misc: ocotp: add i.MX8M support

i.MX8M OCOTP follow same flow as i.MX6Q, but it has 64 banks
and each bank 4 words.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>