omap: &&/|| confusion in iommu_put()

obj can't be both NULL and be an error pointer.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/iommu.c

@@ -827,7 +827,7 @@ EXPORT_SYMBOL_GPL(iommu_get);
  **/
 void iommu_put(struct iommu *obj)
 {
-	if (!obj && IS_ERR(obj))
+	if (!obj || IS_ERR(obj))
 		return;
 
 	mutex_lock(&obj->iommu_lock);