RDMA/ocrdma: Don't memset() buffers we just allocated with kzalloc()

Get rid of obfuscating ocrdma_alloc_mqe() kzalloc() wrapper as all it
did was to make it less visible that the structure was already cleared
on allocation.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>