fix typo causing:
arch/x86/kernel/built-in.o: In function `__unmap_single':
amd_iommu.c:(.text+0x17771): undefined reference to `iommu_area_free'
arch/x86/kernel/built-in.o: In function `__map_single':
amd_iommu.c:(.text+0x1797a): undefined reference to `iommu_area_alloc'
amd_iommu.c:(.text+0x179a2): undefined reference to `iommu_area_alloc'
Signed-off-by: Ingo Molnar <mingo@elte.hu>
07c40e8a1a