ibmvnic: Fix recent errata commit

Sorry, one of the patches I sent in an earlier series
has some dumb mistakes. One was that I had changed the
parameter for the errata workaround function but forgot
to make that change in the code that called it.

The second mistake was a forgotten return value at the end
of the function in case the workaround was not needed.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>