[PATCH powerpc] Fix MAX_STACK_TRACE_ENTRIES too low warning for ppc32

[Li Zhong]

This patch fixes MAX_STACK_TRACE_ENTRIES too low warning for ppc32,
which is similar to commit 12660b17. 

Reported-by: Christian Kujau <lists at nerdbynature.de>
Signed-off-by: Li Zhong <zhong at linux.vnet.ibm.com>
Tested-by: Christian Kujau <lists at nerdbynature.de>
---
 arch/powerpc/kernel/entry_32.S |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index d22e73e..e514de5 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -439,6 +439,8 @@ ret_from_fork:
 ret_from_kernel_thread:
 	REST_NVGPRS(r1)
 	bl	schedule_tail
+	li	r3,0
+	stw	r3,0(r1)
 	mtlr	r14
 	mr	r3,r15
 	PPC440EP_ERR42
-- 
1.7.9.5