[MIPS] page.h: remove __pa() usages.

__pa() was used by virt_to_page() and virt_addr_valid(). These
latter are used when kernel is initialised so __pa() is not
appropriate, we use virt_to_phys() instead.

Futhermore __pa() is going to take care of CKSEG0/XKPHYS
address mix for 64 bit kernels. This makes __pa() more complex
than virt_to_phys() and this extra work is not needed by
virt_to_page() and virt_addr_valid().

Eventually it consolidates virt_to_phys() prototype by making
its argument 'const'. this avoids some warnings that was due
to some virt_to_page() usages which pass const pointer.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 2de4d3c..3049912 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -90,9 +90,9 @@
 	if (!empty_zero_page)
 		panic("Oh boy, that early out of memory?");
 
-	page = virt_to_page(empty_zero_page);
+	page = virt_to_page((void *)empty_zero_page);
 	split_page(page, order);
-	while (page < virt_to_page(empty_zero_page + (PAGE_SIZE << order))) {
+	while (page < virt_to_page((void *)(empty_zero_page + (PAGE_SIZE << order)))) {
 		SetPageReserved(page);
 		page++;
 	}
@@ -448,8 +448,8 @@
 	unsigned long addr;
 
 	for (addr = begin; addr < end; addr += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(addr));
-		init_page_count(virt_to_page(addr));
+		ClearPageReserved(virt_to_page((void *)addr));
+		init_page_count(virt_to_page((void *)addr));
 		memset((void *)addr, 0xcc, PAGE_SIZE);
 		free_page(addr);
 		totalram_pages++;