cmd: Expose a Kconfig option to enable UBIFS commands

Create a new Kconfig entry to allow CMD_UBIFS selection from Kconfig and
add an hidden LZO option that can be selected by CMD_UBIFS.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NJagan Teki <jagan@openedev.com>

cmd/Kconfig

@@ -835,4 +835,12 @@ config CMD_UBI
 	  (www.linux-mtd.infradead.org). Activate this option if you want
 	  to use U-Boot UBI commands.
 
+config CMD_UBIFS
+	tristate "Enable UBIFS - Unsorted block images filesystem commands"
+	select CRC32
+	select RBTREE if ARCH_SUNXI
+	select LZO if ARCH_SUNXI
+	help
+	  UBIFS is a file system for flash devices which works on top of UBI.
+
 endmenu

lib/Kconfig

@@ -135,6 +135,8 @@ config LZ4
 	  frame format currently (2015) implemented in the Linux kernel
 	  (generated by 'lz4 -l'). The two formats are incompatible.
 
+config LZO
+	bool
 endmenu
 
 config ERRNO_STR