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/mpc8313erdb/sdram.c b/board/freescale/mpc8313erdb/sdram.c
index ce6fce5..4e5dfe6 100644
--- a/board/freescale/mpc8313erdb/sdram.c
+++ b/board/freescale/mpc8313erdb/sdram.c
@@ -97,14 +97,14 @@
 	return msize;
 }
 
-phys_size_t initdram(void)
+int initdram(void)
 {
 	volatile immap_t *im = (volatile immap_t *)CONFIG_SYS_IMMR;
 	volatile fsl_lbc_t *lbc = &im->im_lbc;
 	u32 msize;
 
 	if ((im->sysconf.immrbar & IMMRBAR_BASE_ADDR) != (u32)im)
-		return -1;
+		return -ENXIO;
 
 	/* DDR SDRAM - Main SODIMM */
 	msize = fixed_sdram();
@@ -120,5 +120,7 @@
 #endif
 
 	/* return total bus SDRAM size(bytes)  -- DDR */
-	return msize;
+	gd->ram_size = msize;
+
+	return 0;
 }