kernel: Remove unneeded MKDTIMG dependency

Change-Id: Icc1923e922adb50b02252883aa6814101837adfc
diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index 9bcbce3..9f17c3d 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -438,13 +438,12 @@
 ifneq ($(BOARD_CUSTOM_DTBOIMG_MK),)
 include $(BOARD_CUSTOM_DTBOIMG_MK)
 else
-MKDTIMG := $(HOST_OUT_EXECUTABLES)/mkdtimg$(HOST_EXECUTABLE_SUFFIX)
 MKDTBOIMG := $(HOST_OUT_EXECUTABLES)/mkdtboimg.py$(HOST_EXECUTABLE_SUFFIX)
 
 $(DTBO_OUT):
 	mkdir -p $(DTBO_OUT)
 
-$(BOARD_PREBUILT_DTBOIMAGE): $(DTC) $(MKDTIMG) $(MKDTBOIMG) $(DTBO_OUT)
+$(BOARD_PREBUILT_DTBOIMAGE): $(DTC) $(MKDTBOIMG) $(DTBO_OUT)
 $(BOARD_PREBUILT_DTBOIMAGE):
 	@echo "Building dtbo.img"
 	$(hide) find $(DTBO_OUT)/arch/$(KERNEL_ARCH)/boot/dts -type f -name "*.dtbo" | xargs rm -f