powerpc: Add the PC speaker only when requested

This eliminates this minor boot-time debugging error message:

[    1.316451] calling  add_pcspkr+0x0/0x84
[    1.316478] initcall add_pcspkr+0x0/0x84 returned -19 after 0 msecs
Signed-off-by: NEmil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/kernel/setup-common.c

@@ -500,6 +500,7 @@ void __init smp_setup_cpu_sibling_map(void)
 }
 #endif /* CONFIG_SMP */
 
+#ifdef CONFIG_PCSPKR_PLATFORM
 static __init int add_pcspkr(void)
 {
 	struct device_node *np;
@@ -522,6 +523,7 @@ static __init int add_pcspkr(void)
 	return ret;
 }
 device_initcall(add_pcspkr);
+#endif	/* CONFIG_PCSPKR_PLATFORM */
 
 void probe_machine(void)
 {