On newer devices, use dm-default-key to encrypt SD cards

The dm-crypt solution requires a kernel patch that won't be present in
the GKI kernel, while the new metadata encryption system in the GKI
kernel solves this problem in a much cleaner way.

Test: create private volume on Cuttlefish, setting property both ways.
Bug: 147814592
Change-Id: Ie02bd647c38d8101af2bbc47637f65845d312cea
diff --git a/model/Disk.cpp b/model/Disk.cpp
index f92435d..6a6585e 100644
--- a/model/Disk.cpp
+++ b/model/Disk.cpp
@@ -16,11 +16,11 @@
 
 #include "Disk.h"
 #include "FsCrypt.h"
-#include "KeyUtil.h"
 #include "PrivateVolume.h"
 #include "PublicVolume.h"
 #include "Utils.h"
 #include "VolumeBase.h"
+#include "VolumeEncryption.h"
 #include "VolumeManager.h"
 
 #include <android-base/file.h>
@@ -31,8 +31,6 @@
 #include <android-base/strings.h>
 #include <fscrypt/fscrypt.h>
 
-#include "cryptfs.h"
-
 #include <fcntl.h>
 #include <inttypes.h>
 #include <stdio.h>
@@ -507,7 +505,7 @@
     }
 
     KeyBuffer key;
-    if (!generateStorageKey(cryptfs_get_keygen(), &key)) {
+    if (!generate_volume_key(&key)) {
         LOG(ERROR) << "Failed to generate key";
         return -EIO;
     }