Merge tag 'spi-nor/for-5.5' into mtd/next

SPI NOR core changes:
- introduce 'struct spi_nor_controller_ops',
- clean the Register Operations methods,
- use dev_dbg insted of dev_err for low level info,
- fix retlen handling in sst_write(),
- fix silent truncations in spi_nor_read and spi_nor_read_raw(),
- fix the clearing of QE bit on lock()/unlock(),
- rework the disabling of the block write protection,
- rework the Quad Enable methods,
- make sure nor->spimem and nor->controller_ops are mutually exclusive,
- set default Quad Enable method for ISSI flashes,
- add support for few flashes.

SPI NOR controller drivers changes:
- intel-spi:
	- support chips without software sequencer,
	- add support for Intel Cannon Lake and Intel Comet Lake-H flashes.