msg/async/rdma: set/get silence warning

msg/async/rdma: set/get silence warning

functions like gid_to_wire_gid() is not aware of the alignment of the
IBSYNMsg, so we should pass the enclosing structure to it.

to silence warnings like:

ceph/src/msg/async/rdma/Infiniband.cc: In member function ‘int
Infiniband::send_msg(CephContext*, int, IBSYNMsg&)’:
ssd/ceph/src/msg/async/rdma/Infiniband.cc:1123:19: warning: taking
address of packed member of ‘IBSYNMsg’ may result in an unaligned
pointer value [-Waddress-of-packed-
member]
 1123 |   gid_to_wire_gid(&(im.gid), gid);
      |                   ^~~~~~~~~

Signed-off-by: Kefu Chai <kchai@redhat.com>