board: Seagate: 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: Tony Dinh <mibodhi@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>

board/Seagate/dockstar/dockstar.c

@@ -9,7 +9,6 @@
  * Marvell Semiconductor <www.marvell.com>
  */
 
-#include <common.h>
 #include <bootstage.h>
 #include <init.h>
 #include <netdev.h>

board/Seagate/goflexhome/goflexhome.c

@@ -12,7 +12,6 @@
  * Marvell Semiconductor <www.marvell.com>
  */
 
-#include <common.h>
 #include <bootstage.h>
 #include <init.h>
 #include <netdev.h>

board/Seagate/nas220/nas220.c

@@ -8,7 +8,6 @@
  * Marvell Semiconductor <www.marvell.com>
  */
 
-#include <common.h>
 #include <init.h>
 #include <miiphy.h>
 #include <net.h>