Pull NAND changes from Boris Brezillon:
"""
This pull request contains only one notable change:
* Addition of the MTK NAND controller driver

And a bunch of specific NAND driver improvements/fixes. Here are the
changes that are worth mentioning:
* A few fixes/improvements for the xway NAND controller driver
* A few fixes for the sunxi NAND controller driver
* Support for DMA in the sunxi NAND driver
* Support for the sunxi NAND controller IP embedded in A23/A33 SoCs
* Addition for bitflips detection in erased pages to the brcmnand driver
* Support for new brcmnand IPs
* Update of the OMAP-GPMC binding to support DMA channel description
"""