mmc: renesas-sdhi: constify renesas_sdhi_internal_dmac_dma_ops

The structure renesas_sdhi_internal_dmac_dma_ops is only passed as
the second argument to renesas_sdhi_probe, which is const, so
renesas_sdhi_internal_dmac_dma_ops can be const too.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>