nvme: remove the ifdef around nvme_nvm_ioctl

We already have a proper stub if lightnvm is not enabled, so don't bother
with the ifdef.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Keith Busch <[e-mail]>
Reviewed-by: Chaitanya Kulkarni <[e-mail]>

drivers/nvme/host/core.c

···
 	case NVME_IOCTL_SUBMIT_IO:
 		return nvme_submit_io(ns, (void __user *)arg);
 	default:
-#ifdef CONFIG_NVM
 		if (ns->ndev)
 			return nvme_nvm_ioctl(ns, cmd, arg);
-#endif
 		if (is_sed_ioctl(cmd))
 			return sed_ioctl(ns->ctrl->opal_dev, cmd,
 					 (void __user *) arg);