Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/Documentation/ia64/index.rst b/Documentation/ia64/index.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+==================
+IA-64 Architecture
+==================
+
+.. toctree::
+   :maxdepth: 1
+
+   ia64
+   aliasing
+   efirtc
+   err_inject
+   fsys
+   irq-redir
+   mca
+   serial
+   xen