rockchip: Add an MMC driver

Add an MMC driver which supports RK3288, but may also support other SoCs.
It uses the Designware MMC device.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index cae207c..99d0295 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -29,6 +29,7 @@
 obj-$(CONFIG_OMAP_HSMMC) += omap_hsmmc.o
 obj-$(CONFIG_X86) += pci_mmc.o
 obj-$(CONFIG_PXA_MMC_GENERIC) += pxa_mmc_gen.o
+obj-$(CONFIG_ROCKCHIP_DWMMC) += rockchip_dw_mmc.o
 obj-$(CONFIG_SUPPORT_EMMC_RPMB) += rpmb.o
 obj-$(CONFIG_S3C_SDI) += s3c_sdi.o
 obj-$(CONFIG_S5P_SDHCI) += s5p_sdhci.o