iommu: export iommu_area_reserve helper function

x86 has set_bit_string() that does the exact same thing that
set_bit_area() in lib/iommu-helper.c does.

This patch exports set_bit_area() in lib/iommu-helper.c as
iommu_area_reserve(), converts GART, Calgary, and AMD IOMMU to use it.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
index a3b8d4c..5d90074 100644
--- a/lib/iommu-helper.c
+++ b/lib/iommu-helper.c
@@ -30,8 +30,7 @@
 	return index;
 }
 
-static inline void set_bit_area(unsigned long *map, unsigned long i,
-				int len)
+void iommu_area_reserve(unsigned long *map, unsigned long i, int len)
 {
 	unsigned long end = i + len;
 	while (i < end) {
@@ -64,7 +63,7 @@
 			start = index + 1;
 			goto again;
 		}
-		set_bit_area(map, index, nr);
+		iommu_area_reserve(map, index, nr);
 	}
 	return index;
 }