[MTD] [NAND] FSL-UPM: Add wait flags to support board/chip specific delays

The NAND flash on the TQM8548_BE modules requires a short delay after
running the UPM pattern. The TQM8548_BE requires a further short delay
after writing out a buffer. Normally the R/B pin should be checked, but
it's not connected on the TQM8548_BE. The existing driver uses similar
fixed delay points. To manage these extra delays in a more general way,
I introduced the "fsl,ump-wait-flags" property allowing the board-
specific driver to specify various types of extra delay.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>