[MTD] [NAND] fsl_upm: update driver for the new OF bindings

- Get rid of fsl,wait-pattern and fsl,wait-write. I think this isn't
  chip-specific, and we should always do waits. I saw one board that
  didn't need fsl,wait-pattern, but I assume this was the exception
  that proves the rule;
- Get rid of chip-delay. Today there are no users for this, and if
  anyone really need this they should push the OF bindings beforehand;
- Now flash chips should be child nodes of the FSL UPM NAND controller;
- Implement OF partition parsing.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>