Copied from Linux 4.13.
Commit log of 3e9b3112ec74 of Linux explains well why this header
is useful.
Change-Id: I6d565317c573e01eb5df2af5a24982db049e8e08
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
(cherry picked from commit 6990e91f0971b877cd636e646f93587b1afbb284)