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/cmd/mmc.c b/cmd/mmc.c
index 6142ec8..a29650b 100644
--- a/cmd/mmc.c
+++ b/cmd/mmc.c
@@ -5,9 +5,11 @@
  */
 
 #include <common.h>
+#include <blk.h>
 #include <command.h>
 #include <console.h>
 #include <mmc.h>
+#include <part.h>
 #include <sparse_format.h>
 #include <image-sparse.h>