Merge tag 'nand/for-4.13' into MTD

Merge tag 'nand/for-4.13' into MTD

From Boris:
"""
This pull request contains the following core changes:

* addition of on-ecc support to Micron driver
* addition of helpers to help drivers choose most appropriate ECC
  settings
* deletion of dead-code (cached programming and ->errstat() hook)
* make sure drivers that do not support the SET/GET FEATURES command
  return ENOTSUPP use a dummy ->set/get_features implementation
  returning -ENOTSUPP (required for Micron on-die ECC)
* change the semantic of ecc->write_page() for drivers setting the
  NAND_ECC_CUSTOM_PAGE_ACCESS flag
* support exiting 'GET STATUS' command in default ->cmdfunc()
  implementations
* change the prototype of ->setup_data_interface()

A bunch of driver related changes:

* various cleanup, fixes and improvements of the MTK driver
* OMAP DT bindings fixes
* support for ->setup_data_interface() in the fsmc driver
* support for imx7 in the gpmi driver
* finalization of the denali driver rework (thanks to Masahiro for the
  work he's done on this driver)
* fix "bitflips in erased pages" handling in the ifc driver
* addition of PM ops and dynamic timing configuration to the atmel
  driver

And as usual we also have a few minor cleanup/fixes/improvements
patches across the subsystem.
"""