mmc: sdhci: Let drivers define their DMA mask

Add host operation ->set_dma_mask() so that drivers can define their own
DMA masks.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Cc: stable@vger.kernel.org # v4.15 +
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>