stm32mp1: increase device tree size to 20kB

Change-Id: Idee966b6434aa038e54b6e7176749a7b65bdbe84
Signed-off-by: Yann Gautier <yann.gautier@st.com>

plat/st/stm32mp1/stm32mp1_def.h

@@ -111,7 +111,7 @@ enum ddr_type {
 #endif
 
 /* DTB initialization value */
-#define STM32MP_DTB_SIZE		U(0x00004000)	/* 16Ko for DTB */
+#define STM32MP_DTB_SIZE		U(0x00005000)	/* 20Ko for DTB */
 
 #define STM32MP_DTB_BASE		(STM32MP_BL2_BASE - \
 					 STM32MP_DTB_SIZE)