Fix the following build failure:
  LINK  ppc64-softmmu/qemu-system-ppc64
../libhw64/i8259.o: In function `pic_read_irq':
/tmp/portage/app-emulation/qemu-kvm-1.0/work/qemu-kvm-1.0/hw/i8259.c:240: undefined reference to `timer_acks'
/tmp/portage/app-emulation/qemu-kvm-1.0/work/qemu-kvm-1.0/hw/i8259.c:240: undefined reference to `timer_acks'
/tmp/portage/app-emulation/qemu-kvm-1.0/work/qemu-kvm-1.0/hw/i8259.c:241: undefined reference to `timer_ints_to_push'
/tmp/portage/app-emulation/qemu-kvm-1.0/work/qemu-kvm-1.0/hw/i8259.c:242: undefined reference to `timer_ints_to_push'
/tmp/portage/app-emulation/qemu-kvm-1.0/work/qemu-kvm-1.0/hw/i8259.c:242: undefined reference to `timer_ints_to_push'
diff --git a/Makefile.target b/Makefile.target
index 0b610ad..d8b1740 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -275,7 +275,7 @@ obj-ppc-y += virtex_ml507.o
 obj-ppc-$(CONFIG_KVM) += kvm_ppc.o
 obj-ppc-$(CONFIG_FDT) += device_tree.o
 # PowerPC OpenPIC
-obj-ppc-y += openpic.o
+obj-ppc-y += openpic.o i8254.o
 
 # Xilinx PPC peripherals
 obj-ppc-y += xilinx_intc.o