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/gdsys/mpc8308/sdram.c b/board/gdsys/mpc8308/sdram.c
index b7b31fb..5b67a01 100644
--- a/board/gdsys/mpc8308/sdram.c
+++ b/board/gdsys/mpc8308/sdram.c
@@ -66,17 +66,19 @@
 	return get_ram_size(CONFIG_SYS_DDR_SDRAM_BASE, msize);
 }
 
-phys_size_t initdram(void)
+int initdram(void)
 {
 	immap_t *im = (immap_t *)CONFIG_SYS_IMMR;
 	u32 msize;
 
 	if ((in_be32(&im->sysconf.immrbar) & IMMRBAR_BASE_ADDR) != (u32)im)
-		return -1;
+		return -ENXIO;
 
 	/* DDR SDRAM */
 	msize = fixed_sdram();
 
 	/* return total bus SDRAM size(bytes)  -- DDR */
-	return msize;
+	gd->ram_size = msize;
+
+	return 0;
 }