nvmem: core: Fix device reference leak

__nvmem_device_get() make use of bus_find_device() to get the relevant
device and this function increase the reference count of the device
found, however this is not accounted for anywhere. Fix
__nvmem_device_get() and __nvmem_device_put() to properly release this
reference count.
Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/core.c

@@ -811,6 +811,7 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
 			"could not increase module refcount for cell %s\n",
 			nvmem_dev_name(nvmem));
 
+		put_device(&nvmem->dev);
 		return ERR_PTR(-EINVAL);
 	}
 
@@ -821,6 +822,7 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
 
 static void __nvmem_device_put(struct nvmem_device *nvmem)
 {
+	put_device(&nvmem->dev);
 	module_put(nvmem->owner);
 	kref_put(&nvmem->refcnt, nvmem_device_release);
 }