[SRU][F:linux-bluefield][PATCH 0/1] UBUNTU: SAUCE: pka: Fix NULL pointer kfree() issue

[Mahantesh Salimath]

BugLink: https://bugs.launchpad.net/bugs/1931584

SRU Justification:

[Impact]
* Should not free NULL pointer. If the pointer is NULL as a result of memory allocation (kmalloc()),
  only return an error code and don't free (kfree()) a NULL pointer. Even though kfree() won't perform
  any operation if NULL is passed, this is not a good practice.

[Fix]
* Don't free NULL pointer "pka: Fix NULL pointer kfree() issue"

[Test Case]
* No change in functionality.

[Regression Potential]
* Regression can be considered very low as the pointer won't be kfree()'d only in the case of it
  being NULL. This is functionally equivalent to passing NULL pointer to kfree() as no operation will be
  performed in this case.