[PATCH] powerpc/security: Fix build break

[Joel Stanley <joel@jms.id.au>]

This fixes a build break introduced in with the recent round of CPU
bug patches.

  arch/powerpc/kernel/security.c: In function ‘setup_barrier_nospec’:
  arch/powerpc/kernel/security.c:59:21: error: implicit declaration of
  function ‘cpu_mitigations_off’ [-Werror=implicit-function-declaration]
    if (!no_nospec && !cpu_mitigations_off())
                       ^~~~~~~~~~~~~~~~~~~

Fixes: 782e69efb3df ("powerpc/speculation: Support 'mitigations=' cmdline option")
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
This should be applied to the 4.14 and 4.19 trees. There is no issue
with 5.1. The commit message contains a fixes line for the commit in
Linus tree.
---
 arch/powerpc/kernel/security.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index e9af5d9badf2..68d4ec373cfc 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -4,6 +4,7 @@
 //
 // Copyright 2018, Michael Ellerman, IBM Corporation.
 
+#include <linux/cpu.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
 #include <linux/seq_buf.h>
-- 
2.20.1