Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst
index a3233da..ad494da 100644
--- a/Documentation/userspace-api/index.rst
+++ b/Documentation/userspace-api/index.rst
@@ -20,6 +20,7 @@
    seccomp_filter
    unshare
    spec_ctrl
+   accelerators/ocxl
 
 .. only::  subproject and html