mmc: renesas-sdhi, tmio: make dma more modular

Refactor DMA support to allow it to be provided by a set of call-backs
that are provided by a host driver. The motivation is to allow multiple
DMA implementations to be provided and instantiated at run-time.

Instantiate the existing DMA implementation from the sh_mobile_sdhi driver
which appears to match the current use-case. This has the side effect
of moving the DMA code from the tmio_core to the sh_mobile_sdhi driver.

A follow-up patch will change the source file for the SDHI DMA
implementation accordingly. Another follow-up patch will re-organise the
SDHI driver removing the need for tmio_mmc_get_dma_ops().

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/tmio_mmc.c

@@ -97,7 +97,7 @@ static int tmio_mmc_probe(struct platform_device *pdev)
 	/* SD control register space size is 0x200, 0x400 for bus_shift=1 */
 	host->bus_shift = resource_size(res) >> 10;
 
-	ret = tmio_mmc_host_probe(host, pdata);
+	ret = tmio_mmc_host_probe(host, pdata, NULL);
 	if (ret)
 		goto host_free;