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/mpc8315erdb/sdram.c b/board/freescale/mpc8315erdb/sdram.c
index fd8968c..947ffab 100644
--- a/board/freescale/mpc8315erdb/sdram.c
+++ b/board/freescale/mpc8315erdb/sdram.c
@@ -92,13 +92,13 @@
 }
 #endif /* CONFIG_SYS_RAMBOOT */
 
-phys_size_t initdram(void)
+int initdram(void)
 {
 	volatile immap_t *im = (volatile immap_t *)CONFIG_SYS_IMMR;
 	u32 msize;
 
 	if ((im->sysconf.immrbar & IMMRBAR_BASE_ADDR) != (u32)im)
-		return -1;
+		return -ENXIO;
 
 	/* DDR SDRAM */
 	msize = fixed_sdram();
@@ -106,6 +106,8 @@
 	if (im->pmc.pmccr1 & PMCCR1_POWER_OFF)
 		resume_from_sleep();
 
-	/* return total bus SDRAM size(bytes)  -- DDR */
-	return msize;
+	/* set total bus SDRAM size(bytes)  -- DDR */
+	gd->ram_size = msize;
+
+	return 0;
 }