NAND FSL UPM: driver re-write using the hwcontrol callback

NAND FSL UPM: driver re-write using the hwcontrol callback

This is a re-write of the NAND FSL UPM driver using the more universal
hwcontrol callback (instead of the cmdfunc callback). Here is a brief
list of furher modifications:

- For the time being, the UPM setup writing the UPM array has been
  removed from the driver and must now be done by the board specific
  code.

- The bus width definition in "struct fsl_upm_nand" is now in bits to
  comply with the corresponding Linux driver and 8, 16 and 32 bit
  accesses are supported.

- chip->dev_read is only set if fun->dev_ready != NULL, which is
  required for boards not connecting the R/B pin.

- A few issue have been fixed with MxMR bit manipulation like in the
  corresponding Linux driver.

Note: I think the "io_addr" field of "struct fsl_upm" could be removed
      as well, because the address is already determined by
      "nand->IO_ADDR_[RW]", but I'm not 100% sure.

This patch has been tested on a TQM8548 modules with the NAND chip
Micron MT29F8G08FABWP.

This patch is based on the following patches posted to this list a few
minutes ago:

  PPC: add accessor macros to clear and set bits in one shot
  83xx/85xx/86xx: add more MxMR local bus definitions

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