[MTD] [NAND] driver extension to support NAND on TQM85xx modules

[MTD] [NAND] driver extension to support NAND on TQM85xx modules

This patch extends the FSL UPM NAND driver from Anton Vorontsov to
support hardware which does not have the R/B pin of the NAND chip
connected, like the TQM8548 module:

- The OF_GPIO dependency has been removed from the Kconfig option
  because GPIO is not needed. The relevant gpio_* function are then
  stubbed out in <linux/gpio.h>.

- It re-introduces the chip-delay property to define an appropriate
  maximum delay time (tR) required for read operations. The binding
  will be documented in a separate patch.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>