ntwdt_open
static int ntwdt_open(dev_t *, int, int, cred_t *);
ntwdt_open, /* open */
ntwdt_open(dev_t *devp, int flag, int otyp, cred_t *credp)
static int ntwdt_open(dev_t *, int, int, cred_t *);
ntwdt_open, /* cb_open */