x86: add packages files to image bootfs

Add files to bootfs image from selected as built-in packages, which want
to install files to targets boot file system.

Signed-off-by: Tomasz Maciej Nowak <tomek_n@o2.pl>

target/linux/x86/image/Makefile

@@ -85,6 +85,7 @@ ifneq ($(CONFIG_GRUB_IMAGES),)
 		-e 's#@ROOT@#$(GRUB_ROOT)#g' \
 		-e 's#@TITLE@#$(GRUB_TITLE)#g' \
 		./grub.cfg > $(KDIR)/root.grub/boot/grub/grub.cfg
+	-$(CP) $(STAGING_DIR_ROOT)/boot/. $(KDIR)/root.grub/boot/
 	PADDING="$(CONFIG_TARGET_IMAGES_PAD)" SIGNATURE="$(SIGNATURE)" PATH="$(TARGET_PATH)" $(SCRIPT_DIR)/gen_image_generic.sh \
 		$(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).img \
 		$(CONFIG_TARGET_KERNEL_PARTSIZE) $(KDIR)/root.grub \
@@ -123,6 +124,7 @@ define Image/Build/iso
 		-e 's#@TIMEOUT@#$(GRUB_TIMEOUT)#g' \
 		-e 's#@TITLE@#$(GRUB_TITLE)#g' \
 		./grub-iso.cfg > $(KDIR)/root.grub/boot/grub/grub.cfg
+	-$(CP) $(STAGING_DIR_ROOT)/boot/. $(KDIR)/root.grub/boot/
 	mkisofs -R -b boot/grub/eltorito.img -no-emul-boot -boot-info-table \
 		-o $(KDIR)/root.iso $(KDIR)/root.grub $(TARGET_DIR)
 endef