mmc: mmci: Add and implement a ->dma_setup() callback for qcom dml

As a first step to improve the variant specific code for mmci, add a
->dma_setup() callback to the struct mmci_host_ops.

To show its use, let's deploy the callback for the qcom dml, which involves
also to the assign the mmci_host_ops pointer from the variant ->init()
callback.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Ludovic Barre <ludovic.barre@st.com>

drivers/mmc/host/mmci.h

@@ -273,6 +273,7 @@ struct variant_data {
 
 /* mmci variant callbacks */
 struct mmci_host_ops {
+	void (*dma_setup)(struct mmci_host *host);
 };
 
 struct mmci_host_next {