board_f: Rename initdram() to dram_init()

This allows us to use the same DRAM init function on all archs. Add a
dummy function for arc, which does not use DRAM init here.

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Dummy function on nios2]
Signed-off-by: Tom Rini <trini@konsulko.com>

board/motionpro/motionpro.c

@@ -118,7 +118,7 @@ static void sdram_start(int hi_addr)
 /*
  * Initalize SDRAM - configure SDRAM controller, detect memory size.
  */
-int initdram(void)
+int dram_init(void)
 {
 	ulong dramsize = 0;
 #ifndef CONFIG_SYS_RAMBOOT