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/am335x_shc_prompt_defconfig b/configs/am335x_shc_prompt_defconfig
index 5886681..b85d50d 100644
--- a/configs/am335x_shc_prompt_defconfig
+++ b/configs/am335x_shc_prompt_defconfig
@@ -32,5 +32,7 @@
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_MMC_OMAP_HS=y
 CONFIG_DOS_PARTITION=y
+CONFIG_ISO_PARTITION=y
+# CONFIG_SPL_ISO_PARTITION is not set
 CONFIG_SYS_NS16550=y
 CONFIG_OF_LIBFDT=y