mtd: spi-nor: parse Serial Flash Discoverable Parameters (SFDP) tables

This patch adds support to the JESD216 rev B standard and parses the SFDP
tables to dynamically initialize the 'struct spi_nor_flash_parameter'.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@microchip.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>