iommu sg: x86: convert gart IOMMU to use the IOMMU helper

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

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: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Muli Ben-Yehuda <mulix@mulix.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c976eb4..4348211 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -466,7 +466,7 @@
 	  If unsure, say Y.
 
 config IOMMU_HELPER
-	def_bool CALGARY_IOMMU
+	def_bool (CALGARY_IOMMU || GART_IOMMU)
 
 # need this always selected by IOMMU for the VIA workaround
 config SWIOTLB