[MIPS] prom_free_prom_memory cleanup

Current prom_free_prom_memory() implementations are almost same as
free_init_pages(), or no-op.  Make free_init_pages() extern (again)
and make prom_free_prom_memory() use it.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/dec/prom/memory.c b/arch/mips/dec/prom/memory.c
index 3aa01d2..5a557e2 100644
--- a/arch/mips/dec/prom/memory.c
+++ b/arch/mips/dec/prom/memory.c
@@ -92,9 +92,9 @@
 		rex_setup_memory_region();
 }
 
-unsigned long __init prom_free_prom_memory(void)
+void __init prom_free_prom_memory(void)
 {
-	unsigned long addr, end;
+	unsigned long end;
 
 	/*
 	 * Free everything below the kernel itself but leave
@@ -114,16 +114,5 @@
 #endif
 		end = __pa(&_text);
 
-	addr = PAGE_SIZE;
-	while (addr < end) {
-		ClearPageReserved(virt_to_page(__va(addr)));
-		init_page_count(virt_to_page(__va(addr)));
-		free_page((unsigned long)__va(addr));
-		addr += PAGE_SIZE;
-	}
-
-	printk("Freeing unused PROM memory: %ldkb freed\n",
-	       (end - PAGE_SIZE) >> 10);
-
-	return end - PAGE_SIZE;
+	free_init_pages("unused PROM memory", PAGE_SIZE, end);
 }