board_f: Drop setup_dram_config() wrapper

By making dram_init_banksize() return an error code we can drop the
wrapper. Adjust this and clean up all implementations.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>

board/zipitz2/zipitz2.c

@@ -69,10 +69,12 @@ void usb_board_stop(void)
 }
 #endif
 
-void dram_init_banksize(void)
+int dram_init_banksize(void)
 {
 	gd->bd->bi_dram[0].start = PHYS_SDRAM_1;
 	gd->bd->bi_dram[0].size = PHYS_SDRAM_1_SIZE;
+
+	return 0;
 }
 
 #ifdef	CONFIG_CMD_MMC