Refactor: make cryptfs.h smaller

Move most of it into cryptfs.cpp, and include cryptfs.h in fewer files.

Bug: 147814592
Test: Treehugger
Change-Id: Ia3592d73e7abc1f07a60538e0978a3033bdea7de
diff --git a/VoldUtil.h b/VoldUtil.h
index 173c598..6ef8cb1 100644
--- a/VoldUtil.h
+++ b/VoldUtil.h
@@ -22,3 +22,5 @@
 extern android::fs_mgr::Fstab fstab_default;
 
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof(*(a)))
+
+#define DATA_MNT_POINT "/data"