build: Fix CM notice aggregation

$(device_notice_file): \

	    $(strip $(wildcard $(TARGET_DEVICE_DIR)/NOTICE.cm)) \

	    | $(ACP)

	@echo Copying device notice: $@

	$(hide) mkdir -p $(dir $@)

	$(hide) $(ACP) $< $@

	$(hide) if [ -f "$(TARGET_DEVICE_DIR)/NOTICE.cm" ]; then \

	    echo Copying device notice: $@; \

	    mkdir -p $(dir $@); \

	    $(ACP) $< $@; \

	fi

# -----------------------------------------------------------------

# Build a keystore with the authorized keys in it, used to verify the