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/Sinovoip_BPI_M3_defconfig b/configs/Sinovoip_BPI_M3_defconfig
index 7518225..0f37741 100644
--- a/configs/Sinovoip_BPI_M3_defconfig
+++ b/configs/Sinovoip_BPI_M3_defconfig
@@ -20,6 +20,7 @@
 # CONFIG_CMD_FLASH is not set
 # CONFIG_CMD_FPGA is not set
 # CONFIG_SPL_DOS_PARTITION is not set
+# CONFIG_SPL_ISO_PARTITION is not set
 CONFIG_AXP_DCDC5_VOLT=1200
 CONFIG_AXP_DLDO3_VOLT=2500
 CONFIG_AXP_SW_ON=y