Always create a kernel defconfig build artifact

It's just easier having it always built for you
(and it really takes no time).

Change-Id: If183cef50b1de0bf228e27bab77607df71350345

build/tasks/kernel.mk

@@ -288,6 +288,8 @@ $(KERNEL_CONFIG): $(KERNEL_OUT_STAMP) $(KERNEL_DEFCONFIG_SRC) $(KERNEL_ADDITIONA
 			echo "Overriding kernel config with '$(KERNEL_CONFIG_OVERRIDE)'"; \
 			echo $(KERNEL_CONFIG_OVERRIDE) >> $(KERNEL_OUT)/.config; \
 			$(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) oldconfig; fi
+	# Create defconfig build artifact
+	$(hide) $(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) savedefconfig
 	$(hide) if [ ! -z "$(KERNEL_ADDITIONAL_CONFIG)" ]; then \
 			echo "Using additional config '$(KERNEL_ADDITIONAL_CONFIG)'"; \
 			$(KERNEL_SRC)/scripts/kconfig/merge_config.sh -m -O $(KERNEL_OUT) $(KERNEL_OUT)/.config $(KERNEL_SRC)/arch/$(KERNEL_ARCH)/configs/$(KERNEL_ADDITIONAL_CONFIG); \