ARM: at91/defconfig: add the XDMA driver

Add the Atmel eXtended DMA Controller driver option. This driver is first used
on SAMA5D4 SoCs and only relevant in sama5_defconfig file.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/arch/arm/configs/sama5_defconfig b/arch/arm/configs/sama5_defconfig
index 69b6700..5fb8256 100644
--- a/arch/arm/configs/sama5_defconfig
+++ b/arch/arm/configs/sama5_defconfig
@@ -178,6 +178,7 @@
 CONFIG_RTC_CLASS=y
 CONFIG_RTC_DRV_AT91RM9200=y
 CONFIG_DMADEVICES=y
+CONFIG_AT_XDMAC=y
 # CONFIG_IOMMU_SUPPORT is not set
 CONFIG_IIO=y
 CONFIG_AT91_ADC=y