Differentiate the MNTTYPE_* and MNTOPT_* constants.

Bug: http://b/27952303
Change-Id: I926593c16143f76b21a65af7f6e1979d0fb44cac
diff --git a/libc/include/mntent.h b/libc/include/mntent.h
index dbade0c..ab40079 100644
--- a/libc/include/mntent.h
+++ b/libc/include/mntent.h
@@ -35,16 +35,17 @@
 
 #define MOUNTED _PATH_MOUNTED
 
-#define MNTTYPE_DEFAULTS "defaults"
 #define MNTTYPE_IGNORE "ignore"
 #define MNTTYPE_NFS "nfs"
-#define MNTTYPE_NOAUTO "noauto"
-#define MNTTYPE_NOSUID "nosuid"
-#define MNTTYPE_RO "ro"
-#define MNTTYPE_RW "rw"
-#define MNTTYPE_SUID "suid"
 #define MNTTYPE_SWAP "swap"
 
+#define MNTOPT_DEFAULTS "defaults"
+#define MNTOPT_NOAUTO "noauto"
+#define MNTOPT_NOSUID "nosuid"
+#define MNTOPT_RO "ro"
+#define MNTOPT_RW "rw"
+#define MNTOPT_SUID "suid"
+
 struct mntent {
   char* mnt_fsname;
   char* mnt_dir;