resync ubi subsystem with linux:

commit 455c6fdbd219161bd09b1165f11699d6d73de11c
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Mar 30 20:40:15 2014 -0700

    Linux 3.14

A nice side effect of this, is we introduce UBI Fastmap support
to U-Boot.
Signed-off-by: NHeiko Schocher <hs@denx.de>
Signed-off-by: NTom Rini <trini@ti.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Sergey Lapin <slapin@ossfans.org>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Joerg Krause <jkrause@posteo.de>

Signed-off-by: NWolfgang Denk <wd@denx.de>
[trini: Fixup common/cmd_io.c]
Signed-off-by: NTom Rini <trini@ti.com>

vmt.c: In function ‘ubi_free_volume’:
vmt.c:681:6: warning: variable ‘err’ set but not used
[-Wunused-but-set-variable]
Signed-off-by: NMarek Vasut <marek.vasut@gmail.com>
Acked-by: NMike Frysinger <vapier@gentoo.org>

Signed-off-by: NWolfgang Denk <wd@denx.de>

This patch adds basic UBI (Unsorted Block Image) support to U-Boot.
It's based on the Linux UBI version and basically has a "OS"
translation wrapper that defines most Linux specific calls
(spin_lock() etc.) into no-ops. Some source code parts have been
uncommented by "#ifdef UBI_LINUX". This makes it easier to compare
this version with the Linux version and simplifies future UBI
ports/bug-fixes from the Linux version.
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NStefan Roese <sr@denx.de>