powerpc/powernv: add NULL check after kzalloc

[ Upstream commit ceffa63 ]

Fixes coccicheck warning:

./arch/powerpc/platforms/powernv/opal.c:813:1-5:
	alloc with no test, possible model on line 814

Add NULL check after kzalloc.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200509020838.121660-1-chenzhou10@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/powerpc/platforms/powernv/opal.c

@@ -811,6 +811,10 @@ static int opal_add_one_export(struct kobject *parent, const char *export_name,
  goto out;
 
  attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+ if (!attr) {
+ rc = -ENOMEM;
+ goto out;
+ }
  name = kstrdup(export_name, GFP_KERNEL);
  if (!name) {
  rc = -ENOMEM;