iommu/vt-d: include conditionally on CONFIG_INTEL_IOMMU_SVM

Commit 6ee1b77 ("iommu/vt-d: Add svm/sva invalidate function")
introduced intel_iommu_sva_invalidate() when CONFIG_INTEL_IOMMU_SVM.
This function uses the dedicated static variable inv_type_granu_table
and functions to_vtd_granularity() and to_vtd_size().

These parts are unused when !CONFIG_INTEL_IOMMU_SVM, and hence,
make CC=clang W=1 warns with an -Wunused-function warning.

Include these parts conditionally on CONFIG_INTEL_IOMMU_SVM.

Fixes: 6ee1b77 ("iommu/vt-d: Add svm/sva invalidate function")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20201115205951.20698-1-lukas.bulwahn@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/intel/iommu.c

@@ -5387,6 +5387,7 @@ static void intel_iommu_aux_detach_device(struct iommu_domain *domain,
 	aux_domain_remove_dev(to_dmar_domain(domain), dev);
 }
 
+#ifdef CONFIG_INTEL_IOMMU_SVM
 /*
  * 2D array for converting and sanitizing IOMMU generic TLB granularity to
  * VT-d granularity. Invalidation is typically included in the unmap operation
@@ -5433,7 +5434,6 @@ static inline u64 to_vtd_size(u64 granu_size, u64 nr_granules)
 	return order_base_2(nr_pages);
 }
 
-#ifdef CONFIG_INTEL_IOMMU_SVM
 static int
 intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
 			   struct iommu_cache_invalidate_info *inv_info)