board: firefly: Remove <common.h> and add needed includes

Remove <common.h> from this board vendor directory and when needed
add missing include files directly.

Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Tom Rini <trini@konsulko.com>

board/firefly/firefly-rk3288/firefly-rk3288.c

@@ -3,7 +3,6 @@
  * (C) Copyright 2015 Google, Inc
  */
 
-#include <common.h>
 #include <hang.h>
 #include <led.h>
 #include <log.h>

board/firefly/firefly-rk3308/roc_cc_rk3308.c

@@ -3,7 +3,6 @@
  * (C) Copyright 2019 Rockchip Electronics Co., Ltd
  */
 
-#include <common.h>
 #include <adc.h>
 #include <asm/arch-rockchip/grf_rk3308.h>
 #include <asm/arch-rockchip/hardware.h>

board/firefly/roc-pc-rk3399/roc-pc-rk3399.c

@@ -3,7 +3,6 @@
  * (C) Copyright 2016 Rockchip Electronics Co., Ltd
  */
 
-#include <common.h>
 #include <dm.h>
 #include <env.h>
 #include <log.h>