powerpc/4xx: Make sam440ep_setup_rtc() init

sam440ep_setup_rtc() is just called by machine_device_initcall() so make
it __init.
Signed-off-by: Yang Shi <yang.shi@windriver.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/44x/sam440ep.c

@@ -70,7 +70,7 @@ static struct i2c_board_info sam440ep_rtc_info = {
 	.irq = -1,
 };
 
-static int sam440ep_setup_rtc(void)
+static int __init sam440ep_setup_rtc(void)
 {
 	return i2c_register_board_info(0, &sam440ep_rtc_info, 1);
 }