mtd: spi-nor: Parse SFDP SCCR Map

mtd: spi-nor: Parse SFDP SCCR Map

Parse just the 22nd dword and look for the 'DTR Octal Mode Enable
Volatile bit'.

SPI_NOR_IO_MODE_EN_VOLATILE should be set just for the flashes
that don't define the optional SFDP SCCR Map. For the others,
let the SFDP do its job and fill the SNOR_F_IO_MODE_EN_VOLATILE
flag. We avoid this way polluting the flash flags when declaring
one.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20201005153138.6437-10-p.yadav@ti.com