mtd: spi-nor: intel-spi: Add support for Intel Emmitsburg SPI serial flash

Intel Emmitsburg has the same SPI serial flash controller as Lewisburg.
Add Emmitsburg PCI ID to the driver list of supported devices.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200615155748.920-1-mika.westerberg@linux.intel.com