[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>
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 7153854..18b9ffe 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -401,7 +401,7 @@
 
 config MTD_NAND_FSL_UPM
 	tristate "Support for NAND on Freescale UPM"
-	depends on MTD_NAND && OF_GPIO && (PPC_83xx || PPC_85xx)
+	depends on MTD_NAND && (PPC_83xx || PPC_85xx)
 	select FSL_LBC
 	help
 	  Enables support for NAND Flash chips wired onto Freescale PowerPC