board: sama5d4_xplained: update to support DM/DT

Update the configuration files to support the device tree and
driver model, so do SPL. The device clock and pins configuration
are handled by the clock and the pinctrl drivers respectively.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Andreas Bießmann <andreas@biessmann.org>
diff --git a/board/atmel/sama5d4_xplained/sama5d4_xplained.c b/board/atmel/sama5d4_xplained/sama5d4_xplained.c
index 47f0bae..6684276 100644
--- a/board/atmel/sama5d4_xplained/sama5d4_xplained.c
+++ b/board/atmel/sama5d4_xplained/sama5d4_xplained.c
@@ -28,10 +28,12 @@
 DECLARE_GLOBAL_DATA_PTR;
 
 #ifdef CONFIG_ATMEL_SPI
+#ifndef CONFIG_DM_SPI
 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
 {
 	return bus == 0 && cs == 0;
 }
+#endif
 
 void spi_cs_activate(struct spi_slave *slave)
 {