x86: use _types.h headers in asm where available

In general, the only definitions that assembly files can use
are in _types.S headers (where available), so convert them.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index 63d49a5..1a5ff24 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -8,7 +8,7 @@
 
 #include <asm/boot.h>
 #include <asm/asm.h>
-#include <asm/page.h>
+#include <asm/page_types.h>
 
 #include <xen/interface/elfnote.h>
 #include <asm/xen/interface.h>