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

Intel Lewisburg chipset exposes the SPI serial flash controller as a PCI
device in the same way than Intel Denverton. Add Intel Lewisburg SPI
serial flash PCI ID to the driver list of supported devices.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>