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/drivers/ata/sata_sandbox.c b/drivers/ata/sata_sandbox.c
index a28ac56..e64cc4a 100644
--- a/drivers/ata/sata_sandbox.c
+++ b/drivers/ata/sata_sandbox.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <blk.h>
 
 int init_sata(int dev)
 {