Add new defines for STM32MP1 platform

To boot on eMMC or SD-cards, STM32MP1 platform needs:
- GPT_IMAGE_ID to read GPT table on those devices
- STM32_IMAGE_ID and IO_TYPE_STM32IMAGE to read images with STM32 header
- IO_TYPE_MMC to have a IO for MMC devices

Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/include/drivers/io/io_storage.h b/include/drivers/io/io_storage.h
index 485ed8c..02308e3 100644
--- a/include/drivers/io/io_storage.h
+++ b/include/drivers/io/io_storage.h
@@ -22,6 +22,8 @@
 	IO_TYPE_DUMMY,
 	IO_TYPE_FIRMWARE_IMAGE_PACKAGE,
 	IO_TYPE_BLOCK,
+	IO_TYPE_MMC,
+	IO_TYPE_STM32IMAGE,
 	IO_TYPE_MAX
 } io_type_t;