Merge tag 'nand/for-4.20' of git://git.infradead.org/linux-mtd into mtd/next

NAND core changes:
- Two batchs of cleanups of the NAND API, including:
  * Deprecating a lot of interfaces (now replaced by ->exec_op()).
  * Moving code in separate drivers (JEDEC, ONFI), in private files
    (internals), in platform drivers, etc.
  * Functions/structures reordering.
  * Exclusive use of the nand_chip structure instead of the MTD one
    all across the subsystem.
- Addition of the nand_wait_readrdy/rdy_op() helpers.

Raw NAND controllers drivers changes:
- Various coccinelle patches.
- Marvell:
  * Use regmap_update_bits() for syscon access.
  * More documentation.
  * BCH failure path rework.
  * More layouts to be supported.
  * IRQ handler complete() condition fixed.
- Fsl_ifc:
  * SRAM initialization fixed for newer controller versions.
- Denali:
  * Fix licenses mismatch and use a SPDX tag.
  * Set SPARE_AREA_SKIP_BYTES register to 8 if unset.
- Qualcomm:
  * Do not include dma-direct.h.
- Docg4:
  * Removed.
- Ams-delta:
  * Use of a GPIO lookup table
  * Internal machinery changes.

Raw NAND chip drivers changes:
- Toshiba:
  * Add support for Toshiba memory BENAND
  * Pass a single nand_chip object to the status helper.
- ESMT:
  * New driver to retrieve the ECC requirements from the 5th ID byte.