spi: dw-pci: Fix Chip Select amount on Intel Elkhart Lake PSE SPI

Intel(R) Programmable Services Engine (Intel(R) PSE) SPI controllers in
Intel Elkhart Lake have two Chip Select signals instead of one.

Reported-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20191018132131.31608-3-jarkko.nikula@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-dw-pci.c

@@ -36,7 +36,7 @@ static struct spi_pci_desc spi_pci_mid_desc_2 = {
 };
 
 static struct spi_pci_desc spi_pci_ehl_desc = {
-	.num_cs = 1,
+	.num_cs = 2,
 	.bus_num = -1,
 	.max_freq = 100000000,
 };