board_f: Drop return value from initdram()

At present we cannot use this function as an init sequence call without a
wrapper, since it returns the RAM size. Adjust it to set the RAM size in
global_data instead, and return 0 on success.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/freescale/t102xqds/spl.c b/board/freescale/t102xqds/spl.c
index a1481e9..c847b01 100644
--- a/board/freescale/t102xqds/spl.c
+++ b/board/freescale/t102xqds/spl.c
@@ -142,7 +142,7 @@
 
 	i2c_init_all();
 
-	gd->ram_size = initdram();
+	initdram();
 
 #ifdef CONFIG_SPL_MMC_BOOT
 	mmc_boot();