Blackfin arch: Add basic irq stack checking for Blackfin

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/arch/blackfin/include/asm/thread_info.h b/arch/blackfin/include/asm/thread_info.h
index 6427693..1d380de 100644
--- a/arch/blackfin/include/asm/thread_info.h
+++ b/arch/blackfin/include/asm/thread_info.h
@@ -44,6 +44,7 @@
  */
 #define THREAD_SIZE_ORDER	1
 #define THREAD_SIZE		8192	/* 2 pages */
+#define STACK_WARN		(THREAD_SIZE/8)
 
 #ifndef __ASSEMBLY__