common: Drop part.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/disk/part_amiga.c b/disk/part_amiga.c
index 5a17d11..7eea60b 100644
--- a/disk/part_amiga.c
+++ b/disk/part_amiga.c
@@ -9,6 +9,7 @@
 #include <env.h>
 #include <ide.h>
 #include "part_amiga.h"
+#include <part.h>
 
 #ifdef CONFIG_HAVE_BLOCK_DEVICE