cmd: Kconfig: Fix CMD_UBIFS dependencies

Remove the ARCH_SUNXI and RBTREE dependencies.
CMD_UBIFS already gets RBTREE from CMD_UBI (from MTD_UBI), and should
the first become independant from the latter, there would likely be a
dependency on MTD_UBI anyway.

Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Jagan Teki <jagan@openedev.com>
Signed-off-by: Karl Beldan <karl.beldan-ext@sagemcom.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

cmd/Kconfig

@@ -1269,8 +1269,7 @@ config CMD_UBIFS
 	tristate "Enable UBIFS - Unsorted block images filesystem commands"
 	depends on CMD_UBI
 	select CRC32
-	select RBTREE if ARCH_SUNXI
-	select LZO if ARCH_SUNXI
+	select LZO
 	default y if NAND_SUNXI
 	help
 	  UBIFS is a file system for flash devices which works on top of UBI.