configs: rockchip: rock960: enable DMA for SDHCI controller

Enable the SDMA controller so the eMMC connected to the SDHCI
controller (sdhci@fe330000) can make use of it.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
diff --git a/configs/rock960-rk3399_defconfig b/configs/rock960-rk3399_defconfig
index 2381f0c..20c9cde 100644
--- a/configs/rock960-rk3399_defconfig
+++ b/configs/rock960-rk3399_defconfig
@@ -35,6 +35,7 @@
 CONFIG_MMC_DW=y
 CONFIG_MMC_DW_ROCKCHIP=y
 CONFIG_MMC_SDHCI=y
+CONFIG_MMC_SDHCI_SDMA=y
 CONFIG_MMC_SDHCI_ROCKCHIP=y
 CONFIG_PMIC_RK8XX=y
 CONFIG_REGULATOR_PWM=y