boot/grub2: fix the cdboot.img source from host to target

This patch updates the location of cdboot.img used, to select the one
from the target directory and not from the host.
The host-grub2 is built only to have access to the Grub tools binaries.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

boot/grub2/grub2.mk

@@ -192,7 +192,7 @@ define GRUB2_INSTALL_IMAGES_CMDS
 			$(GRUB2_BUILTIN_MODULES_$(tuple))
 		$(INSTALL) -D -m 0644 boot/grub2/grub.cfg $(GRUB2_CFG_$(tuple))
 		$(if $(findstring $(GRUB2_PLATFORM_$(tuple)), pc), \
-			cat $(HOST_DIR)/lib/grub/$(tuple)/cdboot.img $(GRUB2_IMAGE_$(tuple)) > \
+			cat $(@D)/build-$(tuple)/grub-core/cdboot.img $(GRUB2_IMAGE_$(tuple)) > \
 				$(BINARIES_DIR)/grub-eltorito.img
 		) \
 	)