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/keymile/km82xx/km82xx.c b/board/keymile/km82xx/km82xx.c
index bbabbcf..51b4571 100644
--- a/board/keymile/km82xx/km82xx.c
+++ b/board/keymile/km82xx/km82xx.c
@@ -291,7 +291,7 @@
 #endif /* CONFIG_SYS_SDRAM_LIST */
 
 
-int initdram(void)
+int dram_init(void)
 {
 	immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
 	memctl8260_t *memctl = &immap->im_memctl;