stm32mp1: Add support for raw NAND boot device

STM32MP1 platform is able to boot from raw NAND devices.
These modifications add this support using the new
raw NAND framework.

Change-Id: I9e9c2b03930f98a5ac23f2b6b41945bef43e5043
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
diff --git a/plat/st/stm32mp1/include/platform_def.h b/plat/st/stm32mp1/include/platform_def.h
index 263e6d6..450a9d4 100644
--- a/plat/st/stm32mp1/include/platform_def.h
+++ b/plat/st/stm32mp1/include/platform_def.h
@@ -51,6 +51,7 @@
 #define MAX_IO_DEVICES			U(4)
 #define MAX_IO_HANDLES			U(4)
 #define MAX_IO_BLOCK_DEVICES		U(1)
+#define MAX_IO_MTD_DEVICES		U(1)
 
 /*******************************************************************************
  * BL2 specific defines.