uml: use PAGE_SIZE in linker scripts

This patch includes page.h header into linker scripts that allow us to
use PAGE_SIZE macro instead of numeric constant.

To be able to include page.h into linker scripts page.h is needed for
some modification - i.e.  we need to use __ASSEMBLY__ and _AC macro

[jdike@linux.intel.com - fixed conflict with as-layout.h]
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-um/page.h

@@ -7,16 +7,20 @@
 #ifndef __UM_PAGE_H
 #define __UM_PAGE_H
 
+#include <linux/const.h>
+
+/* PAGE_SHIFT determines the page size */
+#define PAGE_SHIFT	12
+#define PAGE_SIZE	(_AC(1, UL) << PAGE_SHIFT)
+#define PAGE_MASK	(~(PAGE_SIZE-1))
+
+#ifndef __ASSEMBLY__
+
 struct page;
 
 #include <linux/types.h>
 #include <asm/vm-flags.h>
 
-/* PAGE_SHIFT determines the page size */
-#define PAGE_SHIFT	12
-#define PAGE_SIZE	(1UL << PAGE_SHIFT)
-#define PAGE_MASK	(~(PAGE_SIZE-1))
-
 /*
  * These are used to make use of C type-checking..
  */
@@ -120,4 +124,5 @@ extern struct page *arch_validate(struct page *page, gfp_t mask, int order);
 #include <asm-generic/memory_model.h>
 #include <asm-generic/page.h>
 
-#endif
+#endif	/* __ASSEMBLY__ */
+#endif	/* __UM_PAGE_H */