mei: Drop unnecessary NULL check after container_of

The result of container_of() operations is never NULL unless the embedded
element is the first element of the data structure, which is not the case
here. The NULL check is therefore unnecessary and misleading. Remove it.

This change was made automatically with the following Coccinelle script.

@@
type t;
identifier v;
statement s;
@@

<+...
(
  t v = container_of(...);
|
  v = container_of(...);
)
  ...
  when != v
- if (\( !v \| v == NULL \) ) s
...+>

Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210511045512.2376580-1-linux@roeck-us.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/main.c

@@ -50,8 +50,6 @@ static int mei_open(struct inode *inode, struct file *file)
 	int err;
 
 	dev = container_of(inode->i_cdev, struct mei_device, cdev);
-	if (!dev)
-		return -ENODEV;
 
 	mutex_lock(&dev->device_lock);