[PATCH v2] mtd: nand: automate NAND timings selection

[s.hauer@pengutronix.de (Sascha Hauer)]

This series aims at automating the NAND timings selection which is
currently supposed to be done in each NAND controller driver, thus
simplifying drivers implementation.

As suggested by Boris this version of the series introduces a nand_reset()
function which replaces the several open coded NAND_CMD_RESET commands
in the code. This makes sure we can apply the timing each time after
after reset.

Also I have brought back the conversion patch for teh sunxi driver whic
was part of Boris initial posting. It's untested due to the lack of hardware,
so please test before applying.

Sascha

Changes since v1:
- create a nand_reset() function to create a single place to reset NAND
  chips and to apply timings
- Add patch to convert sunxi driver for automated timing setup
- split into more patches

Changes since the initial posting from Boris:

- Integrate Feedback from Ezequiel Garcia
- When iterating over the chips calling onfi_set_features() for each
  bail out when any of the calls fail, not only the last one.
- When one of the onfi_set_features() calls fail then reset the chipi
  afterwards.
- Drop Sunxi example, add patch for the mxc_nand controller instead.