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/page_64.h b/arch/powerpc/include/asm/page_64.h
index af04acd..c0ce17e 100644
--- a/arch/powerpc/include/asm/page_64.h
+++ b/arch/powerpc/include/asm/page_64.h
@@ -10,6 +10,8 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#include <asm/asm-const.h>
+
 /*
  * We always define HW_PAGE_SHIFT to 12 as use of 64K pages remains Linux
  * specific, every notion of page number shared with the firmware, TCEs,