[MIPS] Add external declaration of pagetable_init() to pgalloc.h

This fixes some sparse warnings.

pgtable-32.c:15:6: warning: symbol 'pgd_init' was not declared. Should it be static?
pgtable-32.c:32:13: warning: symbol 'pagetable_init' was not declared. Should it be static?

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/mm/init.c

@@ -314,8 +314,6 @@ void __init fixrange_init(unsigned long start, unsigned long end,
 }
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES
-extern void pagetable_init(void);
-
 static int __init page_is_ram(unsigned long pagenr)
 {
 	int i;

arch/mips/mm/pgtable-32.c

@@ -11,6 +11,7 @@
 #include <linux/highmem.h>
 #include <asm/fixmap.h>
 #include <asm/pgtable.h>
+#include <asm/pgalloc.h>
 
 void pgd_init(unsigned long page)
 {

arch/mips/mm/pgtable-64.c

@@ -10,6 +10,7 @@
 #include <linux/mm.h>
 #include <asm/fixmap.h>
 #include <asm/pgtable.h>
+#include <asm/pgalloc.h>
 
 void pgd_init(unsigned long page)
 {