nios2: zap initdram

Zap initdram(), as it is not used.
Signed-off-by: NThomas Chou <thomas@wytron.com.tw>
Acked-by: NMarek Vasut <marex@denx.de>

board/altera/nios2-generic/nios2-generic.c

@@ -44,11 +44,6 @@ int checkboard(void)
 	return 0;
 }
 
-phys_size_t initdram(int board_type)
-{
-	return 0;
-}
-
 #ifdef CONFIG_CMD_NET
 int board_eth_init(bd_t *bis)
 {