ecryptfs: miscdev: File headers are not good kernel-doc candidates

Supply description for the 'daemon' param too.

Fixes the following W=1 kernel build warning(s):

 fs/ecryptfs/miscdev.c:19: warning: cannot understand function prototype: 'atomic_t ecryptfs_num_miscdev_opens; '
 fs/ecryptfs/miscdev.c:323: warning: Function parameter or member 'daemon' not described in 'ecryptfs_miscdev_response'

Cc: Tyler Hicks <code@tyhicks.com>
Cc: "Michael A. Halcrow" <mhalcrow@us.ibm.com>
Cc: ecryptfs@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Tyler Hicks <code@tyhicks.com>