fs: btrfs: Add U-Boot fs handlers.

Signed-off-by: Marek Behun <marek.behun@nic.cz>

 create mode 100644 fs/btrfs/Kconfig
 create mode 100644 fs/btrfs/Makefile
 create mode 100644 fs/btrfs/btrfs.c
 create mode 100644 include/btrfs.h
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
new file mode 100644
index 0000000..0173155
--- /dev/null
+++ b/fs/btrfs/Makefile
@@ -0,0 +1,8 @@
+#
+# 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y := btrfs.o chunk-map.o compression.o ctree.o dev.o dir-item.o \
+	extent-io.o hash.o inode.o root.o subvolume.o super.o