iommu-common: move to arch/sparc

This code is only used by sparc, and all new iommu drivers should use the
drivers/iommu/ framework.  Also remove the unused exports.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
diff --git a/lib/Makefile b/lib/Makefile
index ce20696..94203b5 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -147,7 +147,7 @@
 obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o
 
 obj-$(CONFIG_SWIOTLB) += swiotlb.o
-obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o iommu-common.o
+obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
 obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
 obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o
 obj-$(CONFIG_PM_NOTIFIER_ERROR_INJECT) += pm-notifier-error-inject.o