sparc32: Fix page_to_phys().

It doesn't account for phys_base like it should, fix by using
page_to_pfn().

While we're here, make virt_to_page() use pfn_to_page() as well, so we
consistently use the asm/memory-model.h abstractions instead of
open-coding memory model assumptions.
Tested-by: Kristoffer Glembo <kristoffer@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/io_32.h

@@ -8,7 +8,7 @@
 #include <asm/page.h>      /* IO address mapping routines need this */
 #include <asm/system.h>
 
-#define page_to_phys(page)	(((page) - mem_map) << PAGE_SHIFT)
+#define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
 
 static inline u32 flip_dword (u32 l)
 {

arch/sparc/include/asm/page_32.h

@@ -143,7 +143,7 @@ extern unsigned long pfn_base;
 #define phys_to_virt		__va
 
 #define ARCH_PFN_OFFSET		(pfn_base)
-#define virt_to_page(kaddr)	(mem_map + ((((unsigned long)(kaddr)-PAGE_OFFSET)>>PAGE_SHIFT)))
+#define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 
 #define pfn_valid(pfn)		(((pfn) >= (pfn_base)) && (((pfn)-(pfn_base)) < max_mapnr))
 #define virt_addr_valid(kaddr)	((((unsigned long)(kaddr)-PAGE_OFFSET)>>PAGE_SHIFT) < max_mapnr)