staging/rdma/hfi1: Check interrupt registers mapping

staging/rdma/hfi1: Check interrupt registers mapping

This patch tests the interrupt registers when the driver has no access to
its upstream component. In this case, it is highly likely that it is
running in a virtual machine (eg, Qemu-kvm guest). If the interrupt
registers are not mapped properly by the virtual machine monitor, an
error message will be printed and the probing will be terminated. This
will help the user identify the issue. On the other hand, if the driver
is running in a host or has access to its upstream component in some
other VM, it will do nothing.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>