mtd: spi-nor: parse SFDP Sector Map Parameter Table

Add support for the SFDP (JESD216B) Sector Map Parameter Table. This
table is optional, but when available, we parse it to identify the
location and size of sectors within the main data array of the
flash memory device and to identify which Erase Types are supported by
each sector.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>