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/mips/mach-pic32/cpu.c b/arch/mips/mach-pic32/cpu.c
index c96e046..c3194f0 100644
--- a/arch/mips/mach-pic32/cpu.c
+++ b/arch/mips/mach-pic32/cpu.c
@@ -110,7 +110,7 @@
 }
 
 /* initialize the DDR2 Controller and DDR2 PHY */
-int initdram(void)
+int dram_init(void)
 {
 	ddr2_pmd_ungate();
 	ddr2_phy_init();