linux-imx

lightnvm: ensure that nvm_dev_ops can be used without CONFIG_NVM

null_blk defines an empty version of this ops structure if CONFIG_NVM
isn't set, but it doesn't know the type. Move those bits out of the
protection of CONFIG_NVM in the main lightnvm include.

Signed-off-by: Jens Axboe <axboe@fb.com>