xilinx: versal: Use lowest memory for U-Boot

Find and use the lowest memory for Versal to make sure that we keep u-boot
as low as possible and never use memory above u-boot's maximum VA mapping.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/board/xilinx/versal/board.c b/board/xilinx/versal/board.c
index 45cf1d2..3dc7044 100644
--- a/board/xilinx/versal/board.c
+++ b/board/xilinx/versal/board.c
@@ -229,7 +229,7 @@
 
 int dram_init(void)
 {
-	if (fdtdec_setup_mem_size_base() != 0)
+	if (fdtdec_setup_mem_size_base_lowest() != 0)
 		return -EINVAL;
 
 	return 0;