BOOT: Show that no_ipi_broadcast() takes a parameter.

a rather obvious fix given the opening of the function:

...
static __init int no_ipi_broadcast(char *str)
{
        get_option(&str, &no_broadcast);
...
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

arch/x86/mach-default/setup.c

@@ -131,7 +131,7 @@ static __init int no_ipi_broadcast(char *str)
 	return 1;
 }
 
-__setup("no_ipi_broadcast", no_ipi_broadcast);
+__setup("no_ipi_broadcast=", no_ipi_broadcast);
 
 static int __init print_ipi_mode(void)
 {