Add basic verity support to fs_mgr.

This change adds a "verify" fs_mgr flag specifying that
the device in question should be verified.

Devices marked with this flag are expected to have a
footer immediately after their data containing all
the information needed to set up a verity instance.

Change-Id: I10101f2c3240228ee0932e3767fe35e673d2e720
diff --git a/fs_mgr/fs_mgr_priv.h b/fs_mgr/fs_mgr_priv.h
index 465f51e..f284ca6 100644
--- a/fs_mgr/fs_mgr_priv.h
+++ b/fs_mgr/fs_mgr_priv.h
@@ -71,6 +71,9 @@
 #define MF_RECOVERYONLY 0x40
 #define MF_SWAPPRIO     0x80
 #define MF_ZRAMSIZE     0x100
+#define MF_VERIFY       0x200
+
+#define DM_BUF_SIZE 4096
 
 #endif /* __CORE_FS_MGR_PRIV_H */