stm32mp1: remove useless define

Remove STM32MP_DDR_SPEED_DFLT that is not used in STM32MP1 TF-A code.

Change-Id: I780cdc4e93a8a9d997d50f67cfc582acd4a353d6
Signed-off-by: Yann Gautier <yann.gautier@st.com>

plat/st/stm32mp1/stm32mp1_def.h

@@ -34,7 +34,6 @@
 /* DDR configuration */
 #define STM32MP_DDR_BASE		U(0xC0000000)
 #define STM32MP_DDR_MAX_SIZE		U(0x40000000)	/* Max 1GB */
-#define STM32MP_DDR_SPEED_DFLT		528
 
 /* DDR power initializations */
 #ifndef __ASSEMBLY__