intel-iommu: Simplify __intel_alloc_iova()

There's no need for the separate iommu_alloc_iova() function, and
certainly not for it to be global. Remove the underscores while we're at
it.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --cc drivers/pci/intel-iommu.c
Simple merge