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>
diff --git a/arch/powerpc/cpu/ppc4xx/sdram.c b/arch/powerpc/cpu/ppc4xx/sdram.c
index a49bd69..c416bce 100644
--- a/arch/powerpc/cpu/ppc4xx/sdram.c
+++ b/arch/powerpc/cpu/ppc4xx/sdram.c
@@ -150,7 +150,7 @@
 /*
  * Autodetect onboard SDRAM on 405 platforms
  */
-int initdram(void)
+int dram_init(void)
 {
 	ulong speed;
 	ulong sdtr1;
@@ -353,7 +353,7 @@
  *	 so this should be extended for other future boards
  *	 using this routine!
  */
-int initdram(void)
+int dram_init(void)
 {
 	int i;
 	int tr1_bank1;