docs-rst: add crypto API book to pdf output

The crypto API book was added without the bits required to
generate PDF output. Add them.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/conf.py

@@ -351,6 +351,8 @@ latex_documents = [
      'The kernel development community', 'manual'),
     ('core-api/index', 'core-api.tex', 'The kernel core API manual',
      'The kernel development community', 'manual'),
+    ('crypto/index', 'crypto-api.tex', 'Linux Kernel Crypto API manual',
+     'The kernel development community', 'manual'),
     ('doc-guide/index', 'kernel-doc-guide.tex', 'Linux Kernel Documentation Guide',
      'The kernel development community', 'manual'),
     ('driver-api/index', 'driver-api.tex', 'The kernel driver API manual',

Documentation/crypto/conf.py

+# -*- coding: utf-8; mode: python -*-
+
+project = 'Linux Kernel Crypto API'
+
+tags.add("subproject")
+
+latex_documents = [
+    ('index', 'crypto-api.tex', 'Linux Kernel Crypto API manual',
+     'The kernel development community', 'manual'),
+]