board: xen: 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>
diff --git a/board/xen/xenguest_arm64/xenguest_arm64.c b/board/xen/xenguest_arm64/xenguest_arm64.c
index 1d2946f..4c3b9c9 100644
--- a/board/xen/xenguest_arm64/xenguest_arm64.c
+++ b/board/xen/xenguest_arm64/xenguest_arm64.c
@@ -7,7 +7,6 @@
  * (C) 2020 EPAM Systems Inc
  */
 
-#include <common.h>
 #include <log.h>
 #include <cpu_func.h>
 #include <dm.h>