[PATCH] stack: Declare {randomize_,}kstack_offset to fix Sparse warnings

[GONG, Ruiqi]

Fix the following Sparse warnings that got noticed when the PPC-dev
patchwork was checking another patch (see the link below):

init/main.c:862:1: warning: symbol 'randomize_kstack_offset' was not declared. Should it be static?
init/main.c:864:1: warning: symbol 'kstack_offset' was not declared. Should it be static?

Which in fact are triggered on all architectures that have
HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET support (for instances x86, arm64
etc).

Link: https://lore.kernel.org/lkml/e7b0d68b-914d-7283-827c-101988923929@xxxxxxxxxx/T/#m49b2d4490121445ce4bf7653500aba59eefcb67f
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
Signed-off-by: GONG, Ruiqi <gongruiqi1@xxxxxxxxxx>
---
 init/main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/init/main.c b/init/main.c
index e2490387db2b..6aa0fb2340cc 100644
--- a/init/main.c
+++ b/init/main.c
@@ -101,6 +101,10 @@
 #include <linux/stackdepot.h>
 #include <net/net_namespace.h>
 
+#ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET
+#include <linux/randomize_kstack.h>
+#endif
+
 #include <asm/io.h>
 #include <asm/bugs.h>
 #include <asm/setup.h>
-- 
2.25.1