ALSA: sound/ppc/snd_ps3.c: fix error return code

Initialize ret before returning on failure, as done elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
(
if@p1 (\(ret < 0\|ret != 0\))
 { ... return ret; }
|
ret@p1 = 0
)
... when != ret = e1
    when != &ret
*if(...)
{
  ... when != ret = e2
      when forall
 return ret;
}

// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/ppc/snd_ps3.c

@@ -1040,6 +1040,7 @@ static int __devinit snd_ps3_driver_probe(struct ps3_system_bus_device *dev)
 				   GFP_KERNEL);
 	if (!the_card.null_buffer_start_vaddr) {
 		pr_info("%s: nullbuffer alloc failed\n", __func__);
+		ret = -ENOMEM;
 		goto clean_preallocate;
 	}
 	pr_debug("%s: null vaddr=%p dma=%#llx\n", __func__,