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/nios2/cpu/cpu.c b/arch/nios2/cpu/cpu.c
index c1caa65..6c4ec2c 100644
--- a/arch/nios2/cpu/cpu.c
+++ b/arch/nios2/cpu/cpu.c
@@ -150,3 +150,9 @@
 	.ops		= &altera_nios2_ops,
 	.flags		= DM_FLAG_PRE_RELOC,
 };
+
+/* This is a dummy function on nios2 */
+int dram_init(void)
+{
+	return 0;
+}