[PATCH] remove compile warning from serial console initcall

Patch from: "Martin J. Bligh" <mbligh@aracnet.com>

This tiny patch removes the new compiler warning from my build - the new
console_initcall mechanism seems to require int from console_init ...  I made
serial8250_console_init look like con_init

drivers/serial/8250.c

@@ -1982,10 +1982,11 @@ static struct console serial8250_console = {
 	.index		= -1,
 };
 
-static void __init serial8250_console_init(void)
+static int __init serial8250_console_init(void)
 {
 	serial8250_isa_init_ports();
 	register_console(&serial8250_console);
+	return 0;
 }
 console_initcall(serial8250_console_init);