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

The changes in this patch were made automatically using the following
Coccinelle script.

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

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

Link: https://lore.kernel.org/r/20210510041211.2051325-1-linux@roeck-us.netSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>