Revert "Add support for multi-user decryption"

This reverts commit 0b25b1d79b79bc4d45dfff2aaf575e10bd24ef2d.

Reason for revert: Changes need to be made to libtwrpfscrypt to include this patchset. Will cherry-pick this patch later and make necessary modifications.

Change-Id: I7601d7b820129709b05d9b4368573b6f1048de02
diff --git a/crypto/ext4crypt/Ext4CryptPie.h b/crypto/ext4crypt/Ext4CryptPie.h
index 7236bc0..d6d6ecf 100644
--- a/crypto/ext4crypt/Ext4CryptPie.h
+++ b/crypto/ext4crypt/Ext4CryptPie.h
@@ -32,8 +32,8 @@
                              const std::string& secret);
 //bool e4crypt_lock_user_key(userid_t user_id);
 
-/*bool e4crypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial,
-                                  int flags);*/
+bool e4crypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial,
+                                  int flags);
 /*bool e4crypt_destroy_user_storage(const std::string& volume_uuid, userid_t user_id, int flags);
 
 bool e4crypt_destroy_volume_keys(const std::string& volume_uuid);*/