fs/iso9660: enable Joliet extension

We already enable the Rockridge extension by default when building
ISO9660, so let's also enable the Joliet extension which allows to
support Unicode file names and long file names.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Samuel Martin <s.martin49@gmail.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

fs/iso9660/iso9660.mk

@@ -46,7 +46,7 @@ endef
 ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_PREPARATION
 
 define ROOTFS_ISO9660_CMD
-	$(HOST_DIR)/usr/bin/genisoimage -R -b boot/grub/stage2_eltorito \
+	$(HOST_DIR)/usr/bin/genisoimage -J -R -b boot/grub/stage2_eltorito \
 		-no-emul-boot -boot-load-size 4 -boot-info-table \
 		-o $@ $(ISO9660_TARGET_DIR)
 endef