board: stm32: use bi_dram[0].start instead of hardcoded value

Use gd->bd->bi_dram[0].start initialized from DT instead of using
hardcoded CONFIG_SYS_SDRAM_BASE from config file.

Remove unused CONFIG_SYS_RAM_BASE and CONFIG_SYS_SDRAM_BASE defines.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/board/st/stm32f429-evaluation/stm32f429-evaluation.c b/board/st/stm32f429-evaluation/stm32f429-evaluation.c
index fd2109b..8ab2fa5 100644
--- a/board/st/stm32f429-evaluation/stm32f429-evaluation.c
+++ b/board/st/stm32f429-evaluation/stm32f429-evaluation.c
@@ -48,7 +48,7 @@
 
 int board_init(void)
 {
-	gd->bd->bi_boot_params = CONFIG_SYS_SDRAM_BASE + 0x100;
+	gd->bd->bi_boot_params = gd->bd->bi_dram[0].start + 0x100;
 
 	return 0;
 }