powerpc: move ASM_CONST and stringify_in_c() into asm-const.h

This patch moves ASM_CONST() and stringify_in_c() into
dedicated asm-const.h, then cleans all related inclusions.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: asm-compat.h should include asm-const.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index e492368..447cbd1 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -24,6 +24,7 @@
 #define _ASM_POWERPC_PTRACE_H
 
 #include <uapi/asm/ptrace.h>
+#include <asm/asm-const.h>
 
 
 #ifdef __powerpc64__