devfs_mk_dir -- Create a directory in the devfs namespace.
(devfs_handle_t dir, const char * name, unsigned int namelen, void * info);
The handle to the parent devfs directory entry. If this is NULL the
new name is relative to the root of the devfs.
The name of the entry.
The number of characters in name, not including a NULL
terminator. If this is 0, then name must be NULL-terminated and the
length is computed internally.
An arbitrary pointer which will be associated with the entry.
Use of this function is optional. The devfs_register function
will automatically create intermediate directories as needed. This function
is provided for efficiency reasons, as it provides a handle to a directory.
Returns a handle which may later be used in a call to devfs_unregister.
On failure NULL is returned.