stm32mp1: add support for LpDDR3

This change enables LpDDR3 initialization with PMIC.

Change-Id: I2409a808335dfacd69a8517cb8510cee98bb8161
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/plat/st/stm32mp1/stm32mp1_def.h b/plat/st/stm32mp1/stm32mp1_def.h
index 77a95e6..0eba8a6 100644
--- a/plat/st/stm32mp1/stm32mp1_def.h
+++ b/plat/st/stm32mp1/stm32mp1_def.h
@@ -66,6 +66,7 @@
 enum ddr_type {
 	STM32MP_DDR3,
 	STM32MP_LPDDR2,
+	STM32MP_LPDDR3
 };
 #endif