crypto: doc - optimize compilation

The :functions: definition allows the specification of multiple
function references which prevents parsing the header file multiple
times.

Reported-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
6 files changed