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/board/mpl/pati/pati.c b/board/mpl/pati/pati.c
index 7b7b93f..1288f74 100644
--- a/board/mpl/pati/pati.c
+++ b/board/mpl/pati/pati.c
@@ -135,7 +135,7 @@
 /*
  * Get RAM size.
  */
-int initdram(void)
+int dram_init(void)
 {
 	unsigned char board_rev;
 	unsigned long reg;