Revert "iommu: Allow iova to be used without requiring IOMMU_SUPPORT"

Revert 'commit 353649e5 ("iommu: Allow iova to be used without
requiring IOMMU_SUPPORT"). This commit is made unnecessary by
'commit ac6d83cc ("misc: mic: Fix SCIF build failure with
IOMMU_SUPPORT disabled") and will create a conflict upon merging
with 4.3-rc4. The correct long term solution is to move the iova
library from drivers/iommu into lib/iova which will be done in
a future patch.

Cc: David Woodhouse <David.Woodhouse@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>