Add linux/types.h to cryptfs.h

This commit adds <linux/types.h> to cryptfs.h because cryptfs.h uses
`__le16` and `__le32` which are defined in <linux/types.h>.

The absence of <linux/types.h> will become an error after we sort the
headers in the upcoming commits.

Test: cd system/vold && mma
Change-Id: I9930105ee86f80a29295b59596b21335c68a8e23
diff --git a/cryptfs.h b/cryptfs.h
index d6c7dc5..dc7a8c3 100644
--- a/cryptfs.h
+++ b/cryptfs.h
@@ -29,8 +29,10 @@
  * partition.
  */
 
+#include <linux/types.h>
 #include <stdbool.h>
 #include <stdint.h>
+
 #include <cutils/properties.h>
 
 /* The current cryptfs version */