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/freescale/m5275evb/m5275evb.c b/board/freescale/m5275evb/m5275evb.c
index 48ad4a8..5a9831d 100644
--- a/board/freescale/m5275evb/m5275evb.c
+++ b/board/freescale/m5275evb/m5275evb.c
@@ -25,7 +25,7 @@
 	return 0;
 };
 
-int initdram(void)
+int dram_init(void)
 {
 	sdramctrl_t *sdp = (sdramctrl_t *)(MMAP_SDRAM);
 	gpio_t *gpio_reg = (gpio_t *)(MMAP_GPIO);