staging/rdma/hfi1: Extend the offline timeout

The latest version of the 8051 firmware will wait longer
when bringing the link down.  Extend the driver's timeout
to go with that.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>