sh: Clean up PAGE_SIZE definition for assembly use.

We want to be able to use PAGE_SIZE all over the place,
this is the same approach adopted by other architectures..
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

include/asm-sh/page.h

@@ -16,7 +16,13 @@
 
 /* PAGE_SHIFT determines the page size */
 #define PAGE_SHIFT	12
+
+#ifdef __ASSEMBLY__
 #define PAGE_SIZE	(1 << PAGE_SHIFT)
+#else
+#define PAGE_SIZE	(1UL << PAGE_SHIFT)
+#endif
+
 #define PAGE_MASK	(~(PAGE_SIZE-1))
 #define PTE_MASK	PAGE_MASK