Linux: Reduce minimal size requirement for BTRFS support to 16 MiB by using mixed mode for volumes whose size is less than 109 MiB

src/Core/VolumeCreator.h

@@ -21,7 +21,8 @@
 #include <errno.h>
 #endif
 
-#define VC_MIN_BTRFS_VOLUME_SIZE 114294784ULL
+#define VC_MIN_LARGE_BTRFS_VOLUME_SIZE 114294784ULL
+#define VC_MIN_SMALL_BTRFS_VOLUME_SIZE 16777216ULL
 
 namespace VeraCrypt
 {