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/dbau1550_defconfig b/configs/dbau1550_defconfig
index 964d8a8..0a10367 100644
--- a/configs/dbau1550_defconfig
+++ b/configs/dbau1550_defconfig
@@ -9,3 +9,4 @@
 # CONFIG_CMD_FPGA is not set
 # CONFIG_CMD_SETEXPR is not set
 # CONFIG_CMD_NFS is not set
+# CONFIG_ISO_PARTITION is not set