Merge tag 'spi-nor/for-4.21' of git://git.infradead.org/linux-mtd into mtd/next

Core changes:
- Parse the 4BAIT SFDP section
- Add a bunch of SPI NOR entries to the flash_info table
- Add the concept of SFDP fixups and use it to fix a bug on MX25L25635F
- A bunch of minor cleanups/comestic changes