nvmem: correct Broadcom OTP controller driver writes

- use data write offset to write otp data instead of read offset
- use OTP program command 0x8 to write otp with ECC rather than just
command 0xA without ECC

Fixes: 9d59c6e8

 ("nvmem: Add the Broadcom OTP controller driver")
Signed-off-by: Oza Pawandeep <oza.oza@broadcom.com>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>