iommu sg: powerpc: convert iommu to use the IOMMU helper

This patch converts PPC's IOMMU to use the IOMMU helper functions.  The IOMMU
doesn't allocate a memory area spanning LLD's segment boundary anymore.

iseries_hv_alloc and iseries_hv_map don't have proper device
struct. 4GB boundary is used for them.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b94d450..cf030b0 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -256,6 +256,9 @@
 
 	  Most drivers don't have this problem; it is safe to say Y here.
 
+config IOMMU_HELPER
+	def_bool PPC64
+
 config HOTPLUG_CPU
 	bool "Support for enabling/disabling CPUs"
 	depends on SMP && HOTPLUG && EXPERIMENTAL && (PPC_PSERIES || PPC_PMAC)