IB/ehca: use correct destination for memcpy

Using an element of a struct as the address for the memcpy of the whole
struct may introduce a buffer overflow and does not help readability either
simply pass the real thing as first argument to memcpy.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>