[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/gt64120/ev64120/setup.c b/arch/mips/gt64120/ev64120/setup.c
index 99c8d42..477848c 100644
--- a/arch/mips/gt64120/ev64120/setup.c
+++ b/arch/mips/gt64120/ev64120/setup.c
@@ -59,9 +59,8 @@
  */
 extern struct pci_ops galileo_pci_ops;
 
-unsigned long __init prom_free_prom_memory(void)
+void __init prom_free_prom_memory(void)
 {
-	return 0;
 }
 
 /*
diff --git a/arch/mips/gt64120/momenco_ocelot/prom.c b/arch/mips/gt64120/momenco_ocelot/prom.c
index 8677b6d..78f393b 100644
--- a/arch/mips/gt64120/momenco_ocelot/prom.c
+++ b/arch/mips/gt64120/momenco_ocelot/prom.c
@@ -67,7 +67,6 @@
 	add_memory_region(0, 64 << 20, BOOT_MEM_RAM);
 }
 
-unsigned long __init prom_free_prom_memory(void)
+void __init prom_free_prom_memory(void)
 {
-	return 0;
 }
diff --git a/arch/mips/gt64120/wrppmc/setup.c b/arch/mips/gt64120/wrppmc/setup.c
index 429afc4..121188d 100644
--- a/arch/mips/gt64120/wrppmc/setup.c
+++ b/arch/mips/gt64120/wrppmc/setup.c
@@ -93,9 +93,8 @@
 }
 #endif /* WRPPMC_EARLY_DEBUG */
 
-unsigned long __init prom_free_prom_memory(void)
+void __init prom_free_prom_memory(void)
 {
-	return 0;
 }
 
 #ifdef CONFIG_SERIAL_8250