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/esd/pmc440/sdram.c b/board/esd/pmc440/sdram.c
index e962d4c..c379e77 100644
--- a/board/esd/pmc440/sdram.c
+++ b/board/esd/pmc440/sdram.c
@@ -42,7 +42,7 @@
 };
 
 /*
- * initdram -- 440EPx's DDR controller is a DENALI Core
+ * dram_init -- 440EPx's DDR controller is a DENALI Core
  */
 int initdram_by_rb(int rows, int banks)
 {
@@ -107,7 +107,7 @@
 	return 0;
 }
 
-int initdram(void)
+int dram_init(void)
 {
 	phys_size_t size;
 	int n;