mtd: spi-nor: add support for sst26wf016b memory IC

This commit adds support for the SST sst26wf016b flash memory IC.
This IC was tested with  "snps,dw-apb-ssi" SPI controller.
We don't test dual/quad reads however sst26wf016b flash's datasheet
advertises both dual and quad reads (and support of corresponding
commands)

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>