spi: intel: Switch CS before unmasking and after masking interrupts

At this points the slave is ready to deal with the master.

Change-Id: I815d3c577bd0b73100cbf585cc8ca78f180ec713
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
diff --git a/drivers/spi/intel_spi.c b/drivers/spi/intel_spi.c
index 34e37e3..cfef434 100644
--- a/drivers/spi/intel_spi.c
+++ b/drivers/spi/intel_spi.c
@@ -421,10 +421,10 @@
 		return DEV_NOT_CONFIG;
 	}
 
-	_spi_config_cs(dev);
-
 	info->config_func(dev);
 
+	_spi_config_cs(dev);
+
 	irq_enable(info->irq);
 
 	DBG("SPI Intel Driver initialized on device: %p\n", dev);