UBIFS: add re-mount debugging checks

We observe space corrupted accounting when re-mounting. So add some
debbugging checks to catch problems like this.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

diff --cc fs/ubifs/budget.c
Simple merge

diff --cc fs/ubifs/debug.c
Simple merge

diff --cc fs/ubifs/debug.h
Simple merge

diff --cc fs/ubifs/file.c
Simple merge

diff --cc fs/ubifs/lprops.c
Simple merge

diff --cc fs/ubifs/super.c
Simple merge

diff --cc fs/ubifs/ubifs.h
Simple merge