perf/x86/intel/uncore: Drop unnecessary NULL checks after container_of()

The parameter passed to the pmu_enable() and pmu_disable() functions can not be
NULL because it is dereferenced by the caller.

That means the result of container_of() on that parameter can also never be NULL.
The existing NULL checks are therefore unnecessary and misleading. Remove them.

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
  ...+>

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210510224849.2349861-1-linux@roeck-us.net