KVM: rename vtd.c to iommu.c

Impact: file renamed

The code in the vtd.c file can be reused for other IOMMUs as well. So
rename it to make it clear that it handle more than VT-d.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/arch/ia64/kvm/Makefile b/arch/ia64/kvm/Makefile
index 76464dc..cb69dfc 100644
--- a/arch/ia64/kvm/Makefile
+++ b/arch/ia64/kvm/Makefile
@@ -52,7 +52,7 @@
 		coalesced_mmio.o irq_comm.o)
 
 ifeq ($(CONFIG_DMAR),y)
-common-objs += $(addprefix ../../../virt/kvm/, vtd.o)
+common-objs += $(addprefix ../../../virt/kvm/, iommu.o)
 endif
 
 kvm-objs := $(common-objs) kvm-ia64.o kvm_fw.o