mtd-utils: nanddump: Dynamic buffer, increase pagesize/oobsize

mtd-utils: nanddump: Dynamic buffer, increase pagesize/oobsize

The buffers used for dumping page and OOB data needed dynamic
allocation to help eliminate burdens for updating (i.e., every
time there's a new OOB size we don't have to increase the sizes).

Also, there is no need to check flash chips for "standard sizes."
With recent changes to the printing codebase, we should be able to
handle arbitrary sizes with no problem.

More exit operations are now necessary on program failure, so
"goto closeall" is used more liberally.

Also, common.h is included for the use of xmalloc.

[conflicts fixed by Artem]

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>