Based on the Linux v4.3 patch:

  commit 79c452a
  Author:     Cyrille Pitchen <cyrille.pitchen@atmel.com>
  AuthorDate: Fri Sep 18 17:49:25 2015 +0200
  Commit:     Brian Norris <computersforpeace@gmail.com>
  CommitDate: Mon Sep 21 16:49:52 2015 -0700

      mtd: spi-nor: remove unused read_xfer/write_xfer hooks

      struct spi_nor_xfer_cfg and read_xfer/write_xfer hooks were never used by
      any driver. Do some cleanup by removing them.

      Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
      Reviewed-by: Marek Vasut <marex@denx.de>
      Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>