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/imgtec_xilfpga_defconfig b/configs/imgtec_xilfpga_defconfig
index 1e57273..02969da 100644
--- a/configs/imgtec_xilfpga_defconfig
+++ b/configs/imgtec_xilfpga_defconfig
@@ -17,6 +17,7 @@
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_TIME=y
+# CONFIG_ISO_PARTITION is not set
 CONFIG_OF_EMBED=y
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_NETCONSOLE=y