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/drivers/ddr/fsl/main.c b/drivers/ddr/fsl/main.c
index 159c22e..9aa3eec 100644
--- a/drivers/ddr/fsl/main.c
+++ b/drivers/ddr/fsl/main.c
@@ -15,6 +15,8 @@
 #include <fsl_ddr_sdram.h>
 #include <fsl_ddr.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 /*
  * CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY is the physical address from the view
  * of DDR controllers. It is the same as CONFIG_SYS_DDR_SDRAM_BASE for