doc-rst: build PDF of 80211 and gpu sub-project

This allows to build PDF of only the sub-projects, which reduce the
roundtrip compared to build the PDF from the main documentation.
Signed-off-by: NMarkus Heiser <markus.heiser@darmarit.de>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/80211/conf.py

@@ -3,3 +3,8 @@
 project = "Linux 802.11 Driver Developer's Guide"
 
 tags.add("subproject")
+
+latex_documents = [
+    ('index', '80211.tex', project,
+     'The kernel development community', 'manual'),
+]

Documentation/gpu/conf.py

@@ -3,3 +3,8 @@
 project = "Linux GPU Driver Developer's Guide"
 
 tags.add("subproject")
+
+latex_documents = [
+    ('index', 'gpu.tex', project,
+     'The kernel development community', 'manual'),
+]