board: gateworks: venice: determine dram size at runtime

The SPL does not update the memory node with the dram size from EEPROM
but instead we can use get_ram_size which does a simple memory test
to determine the available RAM. Update PHYS_SDRAM_SIZE to 4GiB as that
is the max used on the Venice boards.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Fabio Estevam <festevam@denx.de>
diff --git a/board/gateworks/venice/venice.c b/board/gateworks/venice/venice.c
index 4e05802..5334500 100644
--- a/board/gateworks/venice/venice.c
+++ b/board/gateworks/venice/venice.c
@@ -21,19 +21,10 @@
 
 int board_phys_sdram_size(phys_size_t *size)
 {
-	const fdt64_t *val;
-	int offset;
-	int len;
-
-	/* get size from dt which SPL updated per EEPROM config */
-	offset = fdt_path_offset(gd->fdt_blob, "/memory");
-	if (offset < 0)
+	if (!size)
 		return -EINVAL;
 
-	val = fdt_getprop(gd->fdt_blob, offset, "reg", &len);
-	if (len < sizeof(*val) * 2)
-		return -EINVAL;
-	*size = get_unaligned_be64(&val[1]);
+	*size = get_ram_size((void *)PHYS_SDRAM, PHYS_SDRAM_SIZE);
 
 	return 0;
 }