IB: remove duplicate header files

In hfi.h, the header file opa_addr.h is included twice.
In vt.h, the header file mmap.h is included twice.

Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com>
Acked-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>