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/ds414_defconfig b/configs/ds414_defconfig
index 502d6f8..82f91f4 100644
--- a/configs/ds414_defconfig
+++ b/configs/ds414_defconfig
@@ -28,6 +28,7 @@
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_UBI=y
+CONFIG_ISO_PARTITION=y
 CONFIG_SPL_OF_TRANSLATE=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_BAR=y