powerpc: Remove second definition of STACK_FRAME_OVERHEAD

Since STACK_FRAME_OVERHEAD is defined in asm/ptrace.h and that
is ASSEMBER safe, we can just include that instead of going via
asm-offsets.h.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S
index fe46048..9de6f39 100644
--- a/arch/powerpc/kernel/vector.S
+++ b/arch/powerpc/kernel/vector.S
@@ -5,6 +5,7 @@
 #include <asm/cputable.h>
 #include <asm/thread_info.h>
 #include <asm/page.h>
+#include <asm/ptrace.h>
 
 /*
  * load_up_altivec(unused, unused, tsk)