docs: filesystems: Update code snippets in autofs.rst

Some of the struct definitions now have an autofs packet header.
Reflect these changes by adding a definition of this header and
place it wherever suitable.

Signed-off-by: Jaskaran Singh <jaskaransingh7654321@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Jaskaran Singh 2019-11-17 22:54:35 +05:30 • committed by Jonathan Corbet
commit c11565e887