nvmem: imx-ocotp: Enable i.MX7D OTP write support

After applying patches for both banked access and write timings we can
re-enable the OTP write interface on i.MX7D processors.

Fixes: 0642bac7 ("nvmem: imx-ocotp: add write support")

Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>