IB/hfi1: Move URGENT IRQ enable to hfi1_rcvctrl()

User contexts use the receive URGENT interrupt.  However, enabling
the IRQ SRC in the file_ops module is not as clean as it could be.

Augment the _rcvctl() function to be able to enable/disable the IRQ
source.

Use the new interface from file_ops to enable/disable the IRQ.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Sadanand Warrier <sadanand.warrier@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>