mmc: renesas_sdhi: improve naming of DMA struct

mmc: renesas_sdhi: improve naming of DMA struct

Commit 058db2868cd8 ("mmc: tmio, renesas_sdhi: move struct tmio_mmc_dma
to renesas_sdhi.h") is correct. The DMA struct should be prefixed with
'renesas_sdhi' to avoid confusion about is namespace. Fix some
indentation while here.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Duy Nguyen <duy.nguyen.rh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20221006190452.5316-3-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>