disk: convert CONFIG_ISO_PARTITION to Kconfig

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay73@gmail.com>
diff --git a/configs/dockstar_defconfig b/configs/dockstar_defconfig
index 2b13f00..0e2e18c 100644
--- a/configs/dockstar_defconfig
+++ b/configs/dockstar_defconfig
@@ -16,6 +16,7 @@
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_UBI=y
+CONFIG_ISO_PARTITION=y
 CONFIG_SYS_NS16550=y
 CONFIG_USB=y
 CONFIG_USB_STORAGE=y