ab8500_btemp: Fix error return code

Initialize return variable before exiting on an error path.

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: Julia Lawall <[e-mail]>
Signed-off-by: Anton Vorontsov <[e-mail]>

drivers/power/ab8500_btemp.c

···
 		create_singlethread_workqueue("ab8500_btemp_wq");
 	if (di->btemp_wq == NULL) {
 		dev_err(di->dev, "failed to create work queue\n");
+		ret = -ENOMEM;
 		goto free_device_info;
 	}