Fix this uninitialized variable warning:

  drivers/iommu/intel_irq_remapping.c:986:12: warning: ‘sub_handle’ may be used uninitialized in this function [-Wuninitialized]

GCC is wrong, help it out.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: joro@8bytes.org
Cc: iommu@lists.linux-foundation.org
Cc: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1336460934-23592-3-git-send-email-suresh.b.siddha@intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>