cmd: Remove <common.h> and add needed includes

Remove <common.h> from all "cmd/" files and when needed add
missing include files directly.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/cmd/pxe.c b/cmd/pxe.c
index 21134eb..ae02c28 100644
--- a/cmd/pxe.c
+++ b/cmd/pxe.c
@@ -4,12 +4,12 @@
  * Copyright (c) 2014, NVIDIA CORPORATION.  All rights reserved.
  */
 
-#include <common.h>
 #include <command.h>
 #include <fs.h>
 #include <net.h>
 #include <net6.h>
 #include <malloc.h>
+#include <vsprintf.h>
 
 #include "pxe_utils.h"