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

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

Signed-off-by: Tom Rini <trini@konsulko.com>

board/seeed/linkit-smart-7688/board.c

@@ -3,7 +3,6 @@
  * Copyright (C) 2018 Stefan Roese <sr@denx.de>
  */
 
-#include <common.h>
 #include <init.h>
 #include <asm/io.h>
 #include <linux/bitops.h>

board/seeed/npi_imx6ull/spl.c

@@ -4,7 +4,7 @@
  * Author: Navin Sankar Velliangiri <navin@linumiz.com>
  */
 
-#include <common.h>
+#include <config.h>
 #include <init.h>
 #include <spl.h>
 #include <asm/arch/clock.h>