cbaf_cdid_get() is only used in cbaf_wusb_chid_store().

In the original code cbaf_cdid_get() returns either a negative error
code or a small positive value on error.  I have changed it to
return -ENOENT if there is not enough data available.

In the original code the caller changed the negative error codes to
positive return values.  I've changed it to just return the error
value directly.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>