fs: move some file system to fs/Makefile

This commit moves some subdirectories of fs
from the toplevel Makefile to fs/Makefile
using Kbuild descending feature.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>

fs/Makefile

@@ -7,3 +7,14 @@
 #
 
 obj-y				+= fs.o
+
+obj-y += cbfs/
+obj-y += cramfs/
+obj-y += ext4/
+obj-y += fdos/
+obj-y += jffs2/
+obj-y += reiserfs/
+obj-y += sandbox/
+obj-y += ubifs/
+obj-y += yaffs2/
+obj-y += zfs/