Merge tag 'spi-nor/for-5.7' into mtd/next

SPI NOR core changes:
- move all the manufacturer specific quirks/code out of the core,
to make the core logic more readable and thus ease maintenance.
- move the SFDP logic out of the core, it provides a better
separation between the SFDP parsing and core logic.
- trim what is exposed in spi-nor.h. The SPI NOR controllers drivers
must not be able to use structures that are meant just for the
SPI NOR core.
- use the spi-mem direct mapping API to let advanced controllers
optimize the read/write operations when they support direct mapping.
- add generic formula for the Status Register block protection
handling. It fixes some long standing locking limitations and eases
the addition of the 4bit block protection support.
- add block protection support for flashes with 4 block protection
bits in the Status Register.

SPI NOR controller drivers changes:
- the mtk-quadspi driver is replaced by the new spi-mem
spi-mtk-nor driver. Merge tag 'mtk-mtd-spi-move' into spi-nor/next
to avoid conflicts.